The two Kloss mattresses in this review could hardly feel more different, even though both pair a pillow top with a coil support system. The Beautyrest Harmony Lux Diamond cushions the body deeply and keeps partner movement quiet, while the Mattress 1st Donegal holds you higher and makes turning easier. Trying them side by side is the quickest way to decide whether you need plush pressure relief or firmer support.
Table of Contents
- Which Kloss Mattress Stands Out?
- What Stood Out During Testing?
- How Do These Kloss Mattresses Compare?
- How We Evaluated Each Mattress
- Kloss Mattress: Our Testing Experience
- Where Did Each Mattress Score Best?
- Which Kloss Mattress Should You Choose?
- What Should You Know Before Buying?
- How Do They Compare With Other Mattresses?
- How to Get a More Reliable Showroom Test
- FAQs
Which Kloss Mattress Stands Out?
| Mattress | Overall Score | Pros | Cons | Ideal For |
|---|---|---|---|---|
| Harmony Lux Diamond Ultra Plush | 4.2/5 | Deep pressure relief; excellent motion control | Deep sink; limited closeout stock | Side sleepers; couples |
| Donegal Firm Pillow Top | 4.1/5 | Firm cushioning; easy movement | More motion transfer | Back sleepers; guest rooms |
What Stood Out During Testing?
Harmony Lux Diamond gave Mia noticeably more room at the shoulder and hip, and it kept the surface calmer when a partner moved. Donegal felt firmer and less enveloping, but it supported the lower back more evenly and required less effort when changing positions. Harmony is the stronger choice for pressure relief and motion isolation; Donegal is better for sleepers who value lift and mobility.
How Do These Kloss Mattresses Compare?
| Feature | Harmony Lux Diamond Ultra Plush | Donegal Firm Pillow Top |
|---|---|---|
| Feel | Ultra plush; 3/10 in our firmness check | Firm; 7.5/10 in our firmness check |
| Type | Pocketed-coil pillow top | Innerspring pillow top |
| Height | 17.5 inches | 14.5 inches |
| Cooling materials | InfiniCool Lux; Micro Diamond Memory Foam | EvenCool fabric; Cool Twist gel memory foam |
| Support system | T2 Pocketed Coil | 8-inch 825-coil system |
| Support | Good; deep top can alter heavier sleepers’ alignment | Very good; firmer core holds the body higher |
| Pressure relief | Excellent; deep shoulder and hip cushioning | Good; cushioned without a deep cradle |
| Motion isolation | Excellent | Fair to good |
| Responsiveness | Moderate | Very good |
| Edge support | Fair to good | Good |
| Durability outlook | Good; thick comfort stack needs consistent support | Very good; firmer surface recovered cleanly |
How We Evaluated Each Mattress
Each mattress went through the same evaluation routine, including back- and side-sleep sessions, short stomach-sleep checks, and time spent reading near the edge. We rated support, cooling, pressure relief, motion isolation, responsiveness, edge support, and durability on a 5-point scale.
For repeatable measurements, we recorded the sink from a 44-pound load, the temperature change after 30 minutes, and the time needed for the surface to recover 90% of its height. Motion readings came from a 10-pound ball dropped six inches above the mattress with the sensor placed 12 inches away. Marcus focused on heat and edge stability, Carlos checked alignment and movement, and Mia paid closest attention to shoulder and hip pressure.
Kloss Mattress: Our Testing Experience
Beautyrest Harmony Lux Diamond Ultra Plush
Our Testing Experience
Harmony was immediately softer than Donegal. Mia’s shoulder settled into the pillow top without a sharp pressure point, and her hips stayed cushioned through a full side-sleep session. Marcus sank farther through the midsection, so the same deep contouring that helped Mia made it harder for him to keep his hips level while lying on his back.
The numbers matched that experience. We rated the feel 3/10, and a 44-pound load sank 2.3 inches into the center. After 30 minutes, the surface had warmed by 5.4°F. The motion sensor registered a 0.14g peak after the ball drop, while the foam-and-quilt stack took 2.6 seconds to recover 90% of its height. That slower rebound kept movement quiet but made a quick turn feel more deliberate. The perimeter also compressed noticeably when we sat close to the edge.
What we liked
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The pillow top cushions sensitive shoulders and hips without an abrupt pushback.
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Low motion transfer makes the bed well suited to couples with different schedules.
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The surface stays plush even over the sturdier pocketed-coil core.
Who it is best for
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Lightweight and average-weight side sleepers who want a deep cradle.
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Couples who prioritize fewer disturbances from partner movement.
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Shoppers who have tried the exact closeout model and know they prefer an ultra-plush feel.
Where it falls short
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Heavier back and stomach sleepers may sink too far through the hips.
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The edge feels less secure than Donegal when sitting or sleeping near the side.
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Closeout inventory varies by Kloss location, so size and condition need to be confirmed before purchase.
Pros & Cons
| Pros | Cons |
|---|---|
| Best pressure relief in this review | Too soft for some heavier sleepers |
| Excellent motion isolation | Noticeable edge compression |
| Plush comfort over stable coils | Limited closeout availability |
Details
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Firmness: Ultra plush
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Mattress type: Pocketed-coil pillow top
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Height: 17.5 inches
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Cover: Seaqual sustainable fabric
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Cooling: InfiniCool Lux; Micro Diamond Memory Foam
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Support system: T2 Pocketed Coil
Review Score
| Metric | Score | Remarks |
|---|---|---|
| Support | 4.0 | Stable coils, but the deep top lets heavier hips settle |
| Cooling | 4.3 | Moderate heat rise for such a thick comfort stack |
| Pressure Relief | 4.7 | The strongest shoulder and hip cushioning of the pair |
| Motion Isolation | 4.6 | Low sensor reading and little partner disturbance |
| Responsiveness | 3.8 | Slow rebound makes turning more deliberate |
| Edge Support | 3.9 | Perimeter compression is easy to notice when seated |
| Durability | 4.0 | Thick comfort layers need a stable, compatible base |
| Overall | 4.2 | Best here for plush pressure relief and motion control |
Mattress 1st Donegal Firm Pillow Top
Our Testing Experience
Donegal’s pillow top softened the first contact, but the underlying support arrived much sooner than it did on Harmony. Carlos felt a steadier lift under his lower back, and rolling from side to back required little effort. The firmer surface did not give Mia as much room at the shoulder during a longer side-sleep session, though it never felt like a bare, rigid spring bed.
Our firmness rating was 7.5/10, and the same 44-pound load sank 1.3 inches at the center. The surface warmed by 6.1°F after 30 minutes. Motion reached 0.29g at the sensor, more than twice Harmony’s reading, while the top recovered 90% of its height in 0.9 second. That fast reset made repositioning easy, but a partner’s larger movements were harder to ignore. The edge compressed less than Harmony and felt steadier while sitting to put on shoes.
What we liked
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The firm core supports the lower back without making the quilted surface feel hard.
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Fast recovery helps combination sleepers turn without pushing against a deep cradle.
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The perimeter feels more dependable than Harmony’s for sitting and sleeping near the edge.
Who it is best for
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Back sleepers who want a pillow top without a deep sink.
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Combination sleepers who change positions often during the night.
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Guest rooms where a broadly supportive, firmer feel is more useful than deep contouring.
Where it falls short
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Partner movement is more noticeable than it is on Harmony.
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Side sleepers with sensitive shoulders may need more surface give.
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The cooling materials helped, but temperature control was not a standout strength.
Pros & Cons
| Pros | Cons |
|---|---|
| Supportive firm-with-cushion feel | More motion transfer than Harmony |
| Strong fit for back and combination sleepers | Limited shoulder give for some side sleepers |
| Easy to turn and reposition | Average temperature control |
Details
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Comfort level: Firm
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Mattress type: Innerspring pillow top
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Height: 14.5 inches
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Quilt: EvenCool fabric; PillowSoft Aire
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Comfort layers: Cushion Quilt foam; Cool Twist gel memory foam
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Support system: 8-inch 825-coil system
Review Score
| Metric | Score | Remarks |
|---|---|---|
| Support | 4.2 | Stable posture with enough quilted cushioning |
| Cooling | 4.1 | Comfortable, but warmer than Harmony in our check |
| Pressure Relief | 4.1 | Useful cushioning without Harmony’s deep cradle |
| Motion Isolation | 3.9 | Larger partner movements travel across the surface |
| Responsiveness | 4.3 | Quick recovery makes position changes easy |
| Edge Support | 4.1 | Steadier than Harmony for sitting and lying near the side |
| Durability | 4.2 | Firmer surface recovered cleanly after repeat loading |
| Overall | 4.1 | A practical firm pillow top for easier movement |
Where Did Each Mattress Score Best?
| Mattress | Overall | Support | Pressure Relief | Cooling | Motion Isolation | Durability | Responsiveness | Edge Support |
|---|---|---|---|---|---|---|---|---|
| Harmony Lux Diamond Ultra Plush | 4.2 | 4.0 | 4.7 | 4.3 | 4.6 | 4.0 | 3.8 | 3.9 |
| Donegal Firm Pillow Top | 4.1 | 4.2 | 4.1 | 4.1 | 3.9 | 4.2 | 4.3 | 4.1 |
Harmony leads where a thick comfort stack helps most: pressure relief and motion isolation. Donegal scores better for support, responsiveness, edge support, and its short-cycle durability outlook. The 0.1-point overall difference matters less than the feel: Harmony lets you settle in, while Donegal keeps you closer to the surface.
Which Kloss Mattress Should You Choose?
Choose Harmony Lux Diamond if pressure relief, motion control, and an unmistakably plush feel come first. It makes the most sense for side sleepers and couples who have tried the exact model and are comfortable buying a closeout. Choose Donegal if you want a firmer pillow top, steadier back support, and less resistance when changing positions. Donegal is the safer all-purpose choice; Harmony is the more specialized comfort choice.
What Should You Know Before Buying?
Harmony Lux Diamond is listed by Kloss as a closeout, so the available size, floor-model condition, price, and return terms can differ by location. Donegal is an active listing, but local inventory and promotional pricing can still change. Confirm what is included before paying, especially if a comfort guarantee or foundation is quoted separately.
These scores reflect controlled checks and sleep sessions, not years of ownership. Harmony may allow heavier hips to settle too deeply, while Donegal transfers more motion and can feel too firm at the shoulder for dedicated side sleepers.
How Do They Compare With Other Mattresses?
Saatva Classic is the more flexible premium alternative to Harmony. It comes in three firmness levels and two heights, with a Euro pillow top and dual-coil support. Its direct purchase includes a 365-night trial, in-room setup, and a lifetime warranty. Harmony feels deeper and softer than Saatva’s Plush Soft option, but Saatva is easier to replace or exchange if the first firmness is wrong. That makes Saatva the stronger choice for shoppers who want premium cushioning without relying on closeout inventory.
Brooklyn Bedding Signature Hybrid is the value-oriented alternative to Donegal. It offers soft, medium, and firm feels, plus an optional pillow-top upgrade, and arrives with a 120-night trial. Donegal has the advantage if you want to lie on the mattress locally before buying and prefer a straightforward firm pillow top. The Signature Hybrid gives you more configuration choices and stronger online purchase protections, though its list price sits above Donegal’s current sale tier.
How to Get a More Reliable Showroom Test
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Spend at least 10 minutes in your usual sleep position; a quick hand press will not reveal hip alignment or shoulder pressure.
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Keep your pillow height close to what you use at home so neck position does not distort the mattress feel.
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If you sleep with a partner, have them roll over while you stay still and compare how much movement reaches your side.
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Test the edge by sitting where you normally put on shoes and by lying close to the side.
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Ask whether the exact mattress is new stock, a floor model, or a closeout, then get the return and comfort-guarantee terms in writing.
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Use a supportive foundation that meets the manufacturer’s requirements; an unstable base can feel like weak mattress support.
FAQs
Which mattress was best for shoulder pressure?
Harmony Lux Diamond gave the shoulder and hip more room to settle and earned the higher pressure-relief score. It is the better fit for side sleepers who find firm pillow tops push too sharply against the shoulder.
Which model handled partner movement better?
Harmony Lux Diamond isolated motion more effectively. Its sensor reading was less than half Donegal’s in the same ball-drop check.
Which one felt easier to move on?
Donegal was easier to move on because its surface recovered faster and did not let the body sink as deeply. Combination sleepers should notice the difference right away.
Which Kloss model makes more sense for a guest room?
Donegal is the safer guest-room choice. Its firm, lightly cushioned feel is easier for a wider range of back and combination sleepers than Harmony’s deep ultra-plush cradle.
