Not that impressive when compared to SF4
I'm not sure if it was enough to take it over from SF4 because it didn't seem like much value was added to it. If Super SF4 came out as a whole instead of SF4 and then this one, it would've been a 10/10 for me. Capcom is trying to ride the gravy train by releasing Super SF4 Arcade edition so I think that's going to be a minor improvement again. Hopefully it'll just be an add-on to Super SF4 instead of buying a whole new game.
The character roster is big but I felt it's too big! Maybe they should've added more locations to match. The character roster on SF4 seemed just right. I do like some of the extra characters, particurlarly the turbo edition characters and they play well but it's just too much for my liking. It almost seems overwhelming playing with all of them actually.
The character balancing is pretty good I must say. There's no one super character, all of them have been balanced but it's a matter of luck who you get as your opponent as some will be particularly powerful against your list of attacks.
Conclusion, if you haven't played SF4, then buy Super SF4!