Multiplayer has always been the best part about DDR, and SuperNOVA offers some great improvements here. The new two-player battle mode puts a competitive twist on the already addictive head-to-head mode. There's also full online multiplayer support, and tough offline head-to-head is still best for competitive dancing.
If you're not a serious DDR fan, then playing any one of the games in the series means you've basically played them all. Still, SuperNOVA is a riot to play against live competitors, and makes a perfect entry point for series newcomers and a must play for any fan.