In comparison? There's no doubt that it'll be noticably worse. Hey, I love my PS2, I have like 98 games for it (incidentally, I have about 58 for 'Cube and 53 for Xbox), so I don't really play favourtism. But every single game that has appeared on the PS2 and one - or both - of the other systems aside from MGS2 (I blame Konami's laziness for that one) has been a lot lower on the technological scale than the 'Cube and Xbox. Xbox has a slightly noticable edge on the 'Cube, but the 'Cube pounds on the PS2 (and Xbox just wastes it). You should have seen Starcraft: Ghost at E3 last year, it was insane. You would think the PS2 version was on the PS1 and usually people develop for the PS2 first.
It's simple: PS2 has so many releases that don't appear anywhere else you're an idiot if you don't have one. Same with the 'Cube really, but there are less and aimed at a different audience (those who love "games" not "cool"; unfortunately, they haven't figured out how to combine the two). But there's absolutely no reason to get a game for the PS2 if it appears on either of the other two unless there's bonus content. Same game, same gameplay, controllers are basically interchangable (except for those stuck in their ways), so the difference comes in 2 things: price and graphics. If the PS2 version is going to get destroyed in both, why would you get it? Especially now that a used GC is the price of a new PS2 game. That means you'll get a 'Cube and the game for about 1/2 the price (or less) of the PS2 version (depending how good you are at finding deals).
Capcom has already said there won't be bonus content, so unless that changes, it just doesn't make logical sense in any way to go for the inferior version, there's nothing to suck you in.