I am a generation behind as far as gaming is concerned due to costs of new vs. used systems, new vs. used games, current vs. previous generation, etc.
Easy choice PS3. Almost everything about PS3 is worse than 360 but you won't know the difference if you never played a 360. More important, you haven't play jack s**t modern games. Buy a PS3 and get PS+. You won't be in the camp that's like, "I play every game the day it comes out so PS+ is a waste." You'll be immediately inundated with more games than you could possibly play and beat in a month and each month you get more and more.
And these aren't like a*s crack quality games. They're good AAA caliber stuff. Everything better about 360 is ruthlessly crushed by PS+ for people that don't buy a ton of new games or haven't played most of what PS+ offers.
Plus, unless you like shooters, PS has a better exclusive library.