Innerspring: The innerspring provides the support for proper spine alignment while you sleep.
Coil Count and Coil Gauge: The thicker the coil (lower gauge) the less the coil count. The thinner the coil (higher guage) the more coils in the mattress.
Edge Support: Increases the usable surface by 10%, and helps prolong the life of your mattress. "S" Posturpedic is a good example that uses edge support.
Non Flip: Almost all new mattresses are non-flip, one-sided mattress. New designs and materials reduce the need to flip, prolonging the life of the mattress, and eliminating the hassle of mattress flipping.
Standard Foams: There are countless types of foam comfort materials with a variety of different feels. Most standard foams are polyurethane, which are more likely to breakdown.
Specialty Foams: Usually visco memory foam and latex which are 100% antimicrobial. These are very durable, relieve pressure points, and help you to sleep undisturbed by your partner.