I agree with his comment actually, I've been playing Playstation since the original PS1, any other controller in my hand just doesn't feel quite right tbh, I also prefer the symmetry of the pad, although ergonomically speaking the 360 fits your hand nicely I prefer holding the a pad with my loosely with fingers rather than it filling the palm of my hand like the 360 pad or even ergonomic mice for that matter on the PC, I usually go for lighter symmetrical mice that can be controlled with your fingers, it's strange I know but I feel too 'locked in' with ergonomic controllers or mice.
Yes for some people there is, A) they may prefer a different controller, B) they may prefer not paying for live, and C) they may prefer playing on a quieter system, which is the main reason why I purchase multi-plats on the PS3.