I own a 360 (that I plan to sell eventually; want a gaming notebook) and I've played a PS3. I wasn't too impressed by the PS3 to tell you the truth. The 360 is alot more managable (in terms of online capabilities and the menu itself) but then again it depends on your tastes.

Personally, compared to PC gaming, none of the next-generation systems are THAT impressive, although the 360 is the closest in my book.