Kat (Gravity Rush) and Emmett Graves (Starhawk) are available as DLC for this game today. They'll be free for everyone for the first two weeks, so I recommend people with PS3s and/or Vitas and/or existing Sony Entertainment Network accounts grab it even if they don't have the game.
I'm still holding out for a $20 sale on PSN before I buy it myself, but I've played a friend's copy a bunch and really enjoy it. The basic gameplay is very different from Super Smash Bros., and not in a bad way; the "arena fighter" structure is similar, but last I checked, that's how a genre works. The "familiar characters" and "nostalgia" issues a lot of people have don't affect me at all either, considering I main Donte and Heihachi, characters from series I have zero emotional investment in.