super street fighter IV is heaps better than SF4. they've made seth less cheap, so now it's far less frustrating and more fun. heaps more characters and they're all unlocked from the start. nice having the old bonus stages (car & barrels) back again. Also each character has two super moves, you choose which to use when you select the character.
upgrade. i got SSF4 for AUD$40 on ebay and I can sell the other for $20. good deal.