Memory foam FTW! I love mine, had it since Jan - completely springless and I don't miss them!!!

Feels firmer than what I would opt for normally, but after it adapts to your body temp it's sooooooo comfortable I no longer wake up stiff or aching

It's also very "dead" in as far as movement goes. Chucking my laptop on my old sprung matress would see it bounce everywhere, but chuck laptop on the mem foam one, and it barely bounces once. So for two people, you won't be affected by each others movements, turning, getting up/getting back into bed etc...