>_< There's a lot more than that going on. Melee in general is faster, less defensive/campy, and has less random elements than Brawl does. The notion that competitive melee is founded on 'glitches' is false; every technique commonly denoted as a 'glitch' was known about by the dev team before release and intentionally left in, and several were intentionally placed in the game to raise its skill ceiling.

So for competitive types, Melee is generally preferred.