hmm how is the online community on those games? just want something with a good story mode and an occasional online match
If you like anime, the story mode in BB is supposed to be good, but I've always found it annoying, personally.
The story in MK9 is typical cheesy MK stuff, but it's a lot of cutscenes and is reasonably long. I've played through it twice now and thought it was fun both times (PS3 then Vita).
I'd say Blazblue is more complex in terms of techniques you can learn as the game goes on... MK9 is a lot more basic, I think, with the most complex things being EX moves, supers, and combo breakers.
MK9 also has a ton of mini games, including a really fun fruit ninja spinoff called test your slice.
You can't go wrong with either, really.
As far as the online community goes, I don't know about BBCS2E since I don't own it on Vita; and I haven't tried ranked or random matches in MK9 -- but for the most part, the Vita version of the game has netcode superior to the console version in every way -- I played about 20 matches with a friend one night and most of the time there wasn't noticeable lag at all.
With the new $24.99 price, I might consider getting Extend on Vita since I skipped it on PS3 (I bought the overpriced character DLC for CS and didn't think $40 was worth it just for Relius). Chrono Phantasma looks nice, but I'd probably get that on PS3 instead of Vita.
Mostly my reasoning. I'm still holding a grudge against Arc for the BBCS2 > BBCS2E transition and currently on the fence about CP. I love the art style and the gameplay, but my group of friends who play fighting games decided they would move on to something else, so I got all of 2 nights of BBCS2E in for $40. After paying the $25 for the character DLC for CS2, I'm bitter.