We all knew Capcom was going to pull this stunt the moment Street Fighter II came out. After milking the first two versions of the game to see who would bite, it's finally made good and released Super Street Fighter II, the last in the line of SFII games to see a release on the SNES. It's got a boatload of new features, including four new characters (making 16 total), tournament and group modes for playing
with multiple people, and additional single-player modes to test your might against the computer. You could say that it's the ultimate Street Fighter II experience.
And it is ... almost. I personally feel that the fighting action in Street Fighter II Hyper Fighting is slightly better. It's more straightforward and down-to-earth. I think Super Street Fighter II began the road to the complexity that is prevalent in modern fighting games. They're still fun, of course, but a simple, straight-out slugfest is good to have, too. So while you lose a little bit in SSFII, the extra modes and new characters more than make up for it. But don't feel screwed if you bought Hyper Fighting, since it's just as good of a fighting game.