After approximately 6.3 seconds of thinking I decided Tekken. Why?
While SF is undeniably the more technical one and actually requires skill, Tekken is generally much more fun to play. I think competitive games must always have an element of randomness. A game is much more fun to play if you're not losing or winning all the time. In Tekken both players win or lose from time to time, even if they're not equally skilled. This isn't the case with SF, so the other player has to be quite close to your skill level to enjoy SF. That's what I think, at least.