Generally the graphics on 360 have a lot finer detail than the PS3. When a multiformat title is released 9 outta 10 times the 360 looks better and both play the same. The is an argument that the PS3 version runs better, but I'm now thinking that the improved visuals are worth a drop in a few frames of animation when things get too crazy.
Online wise, the 360 again has an edge. Yes, charging for Live is a fucking disgrace, but the downloads are much faster and it is easier to play with your friends. Online games? Xbox Live Arcade and (especially) Xbox Live Indie Games are fantastic and over shadow most of the PSN exclusives.
XBLA and XBLIG has trails for EVERY GAME! there are PS Minis that I can't even find trailers for on YouTube!!
I'm not saying PS3 sucks, the exclusives on PS3 far exceed the 360. Killzone, Uncharted, Resistance far out class Halo, Fable, Gears. Also, Move is far better for gaming than Kinect.
But where 95% of games are multiformat why choose the PS3 version unless there are extra content (Arkham Asylum Joker Playable).
That's all, just thought I'd share my current position.