I have both, the Xbox 360 is far the better console as far as the complete package goes, Xbox live is worth every penny of the £25 or whatever it costs now on cdkeys for a year.
Xbox live is far superior to PS plus , not that you need plus for the ps3 to go online, but the free games on xbox are brilliant, for example this month you get Gears of War Judgement day and Terarria, second half of the month we are getting Assassins Creed:Black Flag and Army of Two: Devils Cartel. The Xbox live deals are also really good, in the past I have bought Red Dead for £4, Tomb Raider for a fiver, Fable 2 and 3 for £4 each, LA Noir for a fiver etc etc.
I only use my Ps3 to play The Last of Us and Gran Turismo 6 with my steering wheel (which I bought to be able to play Assetto Corsa on the pc, Driveclub and Project Cars on the ps4).
Modern Xbox's are still light years behind a ps3 in the reliability stakes, I had a 250gb slim that died with the "red dot of death", out of warranty it cost me £70 to have replaced through Microsoft, not cheap, while I have had my PS3 for twice as long and it hasn't ever skipped a beat
TL : DR
PS3
+ The last of us exclusive is worthy of the console alone
+ Gran Turismo 6
+ Good as a media device for watching movies on networked devices
+ Reliable
+ Upgrade to hard drive is really easy, I installed a ps4 500gb hard drive in literally 10 minutes and had it installed, restoring my game saves etc took time on top of course as well as re-downloading games
- PS plus free games (if you sign up) aren't yours to keep once your sub expires
- Interface isn't as good
360
+ Xbox live is brilliant
+ Exclusives such as Forza (though 4 nearly became a DLC riddled pile of w*nk)
+ Cheap games on market place
+ Far Better controller
- Still unreliable
- Can't upgrade HD, only add USB drives
I will blame the wine for my eratic write up