Does it have accurate spring simulation? I've had other sleep games where the mattress modelling is terrible. Need For Sleep makes the bed feel like you can fall asleep in 2 seconds and never fall out, even when you're tossing and turning at 300mph (movements per hour).
How is the audio? I don't want my snores to sound synthesized, but at the same time I don't really want to just listen to samples of someone else snoring - it doesn't react to the way I'm breathing or the angle I'm sleeping at.
Does it have Nordschleep?
Finally, how many people can you fit per bed? I think about 3 is probably more than enough for most people, but you could include some room for spectators and for people to prepare to take over in hardcore "endurance" events.