Original Mattress

I work for Hamuq (Canadian mattress company), I also spend way too much time talking about mattresses so I’ll just give you my honest take. Under $600 at Costco, all of the ones you listed are memory-foam heavy, which can feel okay at first but often lacks support for combo sleepers, especially when you’re a bit heavier on one side of the bed. Here’s a quick rank for medium-firm feel for side + back sleepers: 1. Tuft & Needle 9.5" — Best all-around choice here * Simpler foam, more responsive, less sink-in feel than the rest * Better for combo sleepers than plush gel/memory options 2. Casper Cooling Select 12" — Good second choice * Slightly more contouring than T&N but still balanced * Cooler feel if that matters 3. Sleep Science Align IQ — Might feel too soft * Euro-top + memory tends to contour deeply → pressure points over time 4. Novaform 14" — Too plush for your “medium-firm” goal * Lots of foam, deep sink, can make alignment worse 5. Comfort Tech Serene Foam II — Very basic * Feels inexpensive and lacking support for most adults General advice: at this price point, strong innerspring/hybrid support isn’t in the list, so focus on the least sinky/most responsive foam model, that’s why I lean toward Tuft & Needle or Casper. If you find these still feel too soft or you really want better spinal support, it’s worth considering something built with zoned support and firmer base layers, the type of thing we focus on at Hamuq, because memory foam alone rarely gives the support combo sleepers need long term. Hope this helps!