In the end when we finally got the SNES it came with Super Mario World and I never bought F-Zero (I got SMK instead...).
If I'm being honest you got a good deal there.
Even with my obvious SMK bias, I think it's fair to state SMK is just the more complete game. F-Zero SNES is a fantastic game in its own right though, obviously.
Anyway, F-Zero X is where F-Zero really shines. Not many games can hold a candle next to F-Zero X when it comes to high level video-gaming acrobatics....I'd say it's even superior to Super Mario 64 because of the insane speed.