I have both systems, and find the 360 much, much, much easier to use.
The PS3 is so complicated. Nothing on that thing is easy to do, at all.
Example: I want to send a picture message of some new weed I got to my brother.
360: Hit the guide button, go to messages, take a picture and send it.
PS3: Open the Eyecreate program, take picture, import picture to HD, exit eyecreate, go to messages, and finally send it.
Second Example: I want to talk shit while playing Modern Warfare 2.
360: plug microphone in to bottom of controller.
PS3: find compatible bluetooth headset, go into accessory settings, enter some weird password thing for headset, sync headset, hope it worked
I will never understand why anyone thinks the PS3 is better.