Well when comparing the newest F-Zero to WipEout HD, there's no contest. WipEout wins hands down. But it isn't really fair considering that GX was last gen and Wipeout this gen. The game looks stunning, and gameplay is awesome too. Bonuses like custom soundtracks, ZONES!!!!, online play, sixaxis, etc. make it way better IMO than what F-Zero can offer.
But like I said before, if Nintendo creates a new F-Zero for the Wii then the real comparison will be had. I hope they do make one with online play because other than Mario Kart, nothing has really interested me racing-wise.