Truthfully. The PS3 is alot more powerful then the Xbox360.
The Xbox360 is clearly more popular, but the Ps3 sold the most in September, only losing to the DSi (WTF?!) With Xbox360 in 3rd or 4th, I can't remember which.
Xbox360 has a wider variety of games at the moment. Quite honestly, the "Exclusives" for Xbox360 though are a bit...okay. I love Gears of War I/II and I think Lost Odyssey is a really well done RPG. I don't really like Halo, so that is just an opinion. As for Ps3, we get MGS4 and I guess an extremely hard RPG: Demon Souls.. We get some others, but I can't really remember.
Final Word: Despite the Ps3's horrible start, its coming back. The XBox360 though has already a wide variety of games, and I think the games themselves are cheaper. The PS3 in my opinion is stronger, since Xbox360 has that red ring of lolfailIhatemylifedeath.
Here is a link for both of the systems exclusives.
http://en.wikipedia.org/wiki/List_of...tation_3_games
http://en.wikipedia.org/wiki/List_of_Xbox_360_games