I know two other people who've got one of each, one prefers the 360, the other the PS3 so really, I think it comes down to personal choice. It's not like comparing two PC's where one will actually perform better than another. It's all a matter of opinion.
Personally, the online play for Resistance is swaying me towards my PS3, I'm finding myself on there rather than anything else. But that's just me. It's the first game to really impress me in a long time (having said that, the single player isn't mind blowingly original, but at least it took more than two hours to finish). But again, that's a personal thing, I don't care for single player games, I'm a social gamer, it's all about the multiplayer for me.
I also like being able to sit with a drink and a roomful of mates and play a game... that's where the PC suffers in my opinion.
So, horses for courses, I don't think any of the current crop of machines is 'best' but everyone will have a favourite. Just give them a chance, enjoy the one you've got and don't flame the rest. Don't like it, don't buy it.