The title says it all. I basically bought this as soon as I saw it on the App Store. I didn't read any reviews, and only saw one or two videos of the game in action. I'm glad I wasn't disappointed. I'm really impressed with how well this plays using the touch screen; I could mostly pull some pretty complex combos with ease, but there were some rare occasions when it was difficult to even do a Hadoken. My only gripe with this is that it doesn't have an online multiplayer mode. It does have a bluetooth multplayer mode, however. I can only hope Capcom will acknowledge our demand for an online multiplayer mode and include it in a future update. 
 
This might not have the depth of the console version, but the fact that I now have an excellent SFIV port on my iPhone to play on the go is enough to keep me happy. For those of you who have a PSP, I think it's a good idea that you wait for the rumored PSP port since it's bound to be even better than this one. If you don't have a PSP, however, and you've got an iPhone then I would definitely recommend that you check this out.