I didn't like Soul Calibur IV. It was fun, but not as good as Soul Calibur 2, but DEFINITELY better than 3. To be honest, I think they put in way too many features and that just bogged the game down.
With that said, I choose Street Fighter IV. It's a balanced game, it's not as "button mashy" as Soul Calibur IV, and I like the stylization of SFIV.