I only really ever played the N64 title waaaaay too much in college. We loved that game.
The original is the best. Anyone saying otherwise must have really sucked at the 1st one.
Besides these I've really enjoyed the sonic karting games a lot (maybe even more than the newest Mario Karts), the crash carting when it first came out, and Krazy Racers on GBA as well
Sonic All Stars Racing Transformed is better than Mario Kart 8. I recommend everyone play it, it's probably cheap by now.
SNES version was the only one where I had fun playing in the battle mode.
Battle Mode on MK64 is legit. I don't remember much of battle mode on SNES, though.

The original is the best. Anyone saying otherwise must have really sucked at the 1st one.