strikeforce on ps360 got new character, online coop and that's it. if you don't care about coop i would go with psp version of the game since you can get it for 10$ and it's great pick up & play title.
i would consider also getting Warriors Orochi 2(or just it since it's a massive game) for psp since it is basically ultimate version of Warriors games this gen.
- 100 characters from Dynasty Warriors, Samurai Warriors and few exclusive characters,
- buttload of game modes(even a fighting game with lots of additional modes),
- weapon upgrades and fusion mode,
- 5 different story modes,
- Dream mode with 40 additional stages,
- sidequests,
and it's like 15$ now - for that amount of content it's a steal.