Side-by-side mattress testing · 144+ comparisons published
Updated September 2026
Category
Beautyrest Black L-Class
Serta iSeries NXG 3500 Hybrid
Comfort
8.5/10
Not lab tested
Support
9.6/10
Not lab tested
Cooling
9/10
Not lab tested
Edge Support
9.5/10
Not lab tested
Motion Isolation
8.5/10
Not lab tested
Durability
9.4/10
Not lab tested
Value
8.4/10
8/10
Blank cells mean that model has not completed our instrumented lab protocol, so we publish no measured score for it. We never estimate a number we have not recorded.
Quick Specs Comparison
Spec
Beautyrest Black L-Class
Serta iSeries NXG 3500 Hybrid
Price (Queen)
$2,799
$2,599
Type
Hybrid
Hybrid
Firmness
8/10
6.5/10
Height
13.75 inches
Varies by comfort level
Trial
100 nights
120 nights
Warranty
10 years
10 years
Shipping
Free white glove delivery
Free shipping
Key Advantages
Why Choose Beautyrest Black L-Class
- Firmest model — ideal for back/stomach sleepers
- Highest support rating in the lineup (9.6)
- Excellent for heavier sleepers (250+ lbs)
Why Choose Serta iSeries NXG 3500 Hybrid
- Micro coil layer boosts pressure relief without killing support
- CoolFeel Plus is Serta's strongest cooling package
- Split-head queen and king sizes available