Very good iPhone version compared to Xbox
Capcom was selling the iPhone app fro SFIV at a discounted rate in which the proceeds go to charity (I believe its for the Japan Tsunami charities). It was a bargain, so I went for it and was surprised at how good the game was.
Sure it's not going to be exactly the same at the xbox version, it was only about 260MB in size or somewhere there but it was great for the size.
Great graphics, frames are cut and costumes are limited to two per character. The buttons and 'visual pad' are pretty good. I did find it hard to pull off some of the moves but I suppose you get used to it.
The game itself is quite easy and with the limitations, I still find it a fun game to play because it's meant to be played in short spells on your iPhone. Another good job by Capcom