If you need back support, this Helix Midnight medium-firm mattress is a solid option for a new mattress—no pun intended. She opted for the Helix mattress that’s two inches thicker than its standard mattress, which made it a little harder to move from the box to the bed frame. Comfort: While comfort can be subjective, our editors and contributors kept in mind mattress qualities such as breathability, support, and softness/firmness for the best sleep.