Tried this on Vita and on PS3. It is very tough to do well. My biggest complaint is what I originally feared from the screen shots - it's hard to see what's going on and I keep losing who I am. You kind of need to see what color you reference is "P1", "P2", etc. and keep an eye on that rather than your character. The problem comes in that the color your text is changes every match. I'd rather always be red or whatever because I keep forgetting.
Regardless of that I also wind up following the wrong character lol. It happens less if you are the only tall character (Kratos, Sweet Tooth), but there's so much going on sometimes I find myself watching the other characters not mine! Fat Princess is pretty easy to see.
Another gripe is the weapons switch on you, I'd rather always have circle be your ranged, square fast and triangle heavy. Something like that, but it definitely appears to randomly switch what the buttons do.
Game looks good on both systems. Matches are pretty quick and easy to get into.
I did better on PS3 than Vita but I played first on Vita so there's that too. Either way I did horrible on both, with only two times getting positive points (the rest were negative lol). Both times were with Kratos. I couldn't do a thing with Sly.
I guess I need to play more, and the single player portions in the game might boost your skills too. It just didn't feel like I had a lot of control over my fate. More practice might make it more enjoyable. Plus more characters will be nice. I guess I just still have mixed feelings about how fun it will be if you just get pummeled every time since there isn't anything else online - no story, no big environments to goof around in etc.
EDIT. I'm going to make sure my son plays the beta and gives me input. Even with cross-buy, it's still $55 to drop which could be saved or spent on a game that might get played more. I'm not too worried about the Vita, with LBP and ACIIIL, not to mention Plus coming to Vita, I'm not concerned about content. My son also is way more into the Skyrim, AC landscape of games than fighters. I'm afraid the novelty of seeing sackboy fight Kratos etc. would wear off quickly.
EDIT EDIT. Dang, sittin' here I've almost convinced myself to cancel the pre-order
Too many other games to play, not to mention I can totally see this coming to the PS+ IGC down the road.