Here is is boys n girls
They both offer an online experience, and have some pros and cons. here's the code difference:
MS sells a game console. Sony Sells a Home Multimedia Entertainment System.
XBL is decidedly games focused, specifically focused around cooperative multilayer experiences, and also for hooking up with strangers, and it costs money to play. PSN is free to play, and is focused on the game experience itself, ad unifying family and friends (not random strangers), except within specific-game settings.
XBL provides a slightly better price on games, but worse on content. PSN has more content, and better prices, and is slightly more shallow on games. Since the xBox is billed as an arcade system, and Sony as an entertainment system, the el-cheapo games are not exactly highlighted on PSN, they're looking to move real titles.
The 360 uses XBMC, which is not bad for playing content from your PC, and is a simple interface. PS3 not only plays the content from your PC and Mac, and other sources, it has significantly more entertainment options in addition.
360 plays only digital content, PS3 plays all that, and more MS does not provide, plus DVD and Br video.
I heard someone argue once (not that I necessarily agree) PS3 is for deep gaming experiences and improving the enjoyment overall of being in your living room. 360 is for cheap quick thrills.
Popularity? xbox has it. Community? xbox has it. Price? well, PS3 is technically cheaper if you play games online... more so if you also had to buy a blue-ray player to sit beside your 360.
Oh, and my opinion (and yes, i used both extensively before coming to this conclusion), kinect sucks,nothing more than a novelty and a very limited experience and application to only some genres of games, and only new upcoming titles, and Move is actually more fun to play, has less lag, will have a larger game selection, and will be the winner of this war (unless MS also adds a handheld device to kinect).