Better quality discs, they don't scratch as easily. Good if you aren't good with your games.
PS3 Exclusives such as Rachet & Clank, Uncharted, God of War, etc.
Less advertisements on the homescreen.
Can play Blu-Ray DVDs.
More cost efficient if done correctly, I've had Live for 2+ years, and haven't spent 300 dollars on my Xbox. Which is the cheapest model of PS3.
Better internet interface.
Xbox 360 exclusives suc as Halo, Gears of War, Forza Motorsport 4, Left 4 Dead, etc.
Didn't have people's credit card numbers stolen (I do find this to be a big deal).
Putting the two up against each other, I prefer the Xbox 360 for cost efficiency and Online performance.