sparta is B O R I N G. i saw them live and they were asleep up there. in contrast, mars volta tore the place up. mars volta is musically, tonally, and dynamically more interesting than sparta, and the songs are just stronger. that said, the mars volta are the most pretentious band in the universe. they make tool look a bunch silly goofballs. talk about rock-star ego. i can't stand listening to them just because they are so full of themselves. but i don't listening to sparta either, because they're so dull.
i think neither band is as good as at the drive in, although i didn't think they were super great, either. the blood brothers do what ATDI did, but they do it a lot better (even produced by the same guy).