I've raced motocross, supercross, and harescrambles.
A full mx track is my least favorite, possibly because I have the least amount of practice on it...I'm just learning harescrambles......which people think is easy because its trails....butttt try flying through the woods 3rd/4th gear pinned through trees, ruts, etc.....not as easy as everyone thinks.....and an 1 1/2 hour race....it's tough, I didn't think it would be as tough, then I did it....wow.
And I pretty much love supercross too.....unless there's a step up jump....I don't fare well with them :) haha....
But I'd rather race then just ride