Stargate is the best.
I had a World Challenge Soccer and a Street Fighter II, and I liked SFII a lot better than WCS. I'm not sure if I would place WCS lowest though. Some street level games can be fun, but a bit boring in the longer run as well(?). Hard to say when you've played all system3 games, but only owned a few of them. But one thing I'm sure of: Stargate is the best