The Bottom LineThe 10-inch Sleep Number P5 is an adjustable firmness mattress with air chambers for support. Couples with very different comfort preferences rate this model well. However, the technology has its price, and some reviews mention air leakage issues. Both 11-inch mattresses, Casper Wave and Sapira are medium-firm, but Casper Wave is on the softer side of the scale. Both Sapira and Casper Wave offer luxury-like features, Sapira is ranked superior in terms of value for money and customer satisfaction. Casper Wave is good for backache relief, suitable mainly for average and lightweight persons. Sapira features Avena foam, known for its resilience, responsiveness, and pressure-relief. As a result, this mattress is admired equally by side, back, and stomach sleepers. Although Casper Wave is a bit pricier than Sapira, it’s Sapira’s better value that truly sets it apart. Of all the three mattresses in comparison, Sapira is rated better for its comfort, durability, and cooling.