Xbox 360 has a much better user experience. Plus the controller is leaps and bounds ahead of the PlayStation controller. If you go from a long time gaming on a 360 then try to use the PlayStation controller, it feels like a half assed toy. The L2 and R2 buttons which were made sort of trigger like are awkward, the joysticks are in uncomfortable places. It's just not very ergonomic. Also, this is coming from someone who played PlayStation 2 for like 6 years before ever trying an Xbox. I also enjoy the 360 exclusives much more. 360 gets content before other people. Sony's network was hacked, resulting in the spread of thousands maybe even millions of people's personal information. Kinect is far more intuitive and is being put to use far more in games than Move is.
The only thing that is undeniably better on the PS3 is that the online service is free (you get what you pay for, though Xbox Live is better.. it's just a fact) and that you get Blu-Ray capability. However, since 360 is largely viewed as top dog among gamers and developers alike.. when they are designing a game that they intend to be multi-platform, they almost always design it around the Xbox 360 THEN port it over to the PS3. So really in this respect, the 360 is limiting the PS3 in that any game that is multi-platform must be able to fit on the inferior dual-layer DVDs that the 360 uses.. also hampering the motivation for me to buy a PS3 knowing that the vast majority of games will play exactly the same, and that the exclusives just aren't that great for my style of play, online play.. MAG / Killzone 3 are horrible imo, can't even think of any online exclusive that's actually worth buying a PS3 specifically for)