I used to own a PS3 and never really got into the collection of trophies, but I think achievements are much better implemented on xbox. When you manage to get achievement points on a game like Geo Wars you feel like you've accomplished something and they can keep you playing a game that you wouldn't have played so many times until you get all of its achievements.
I think achievements feel more like a natural part of the 360 experiences rather than a tacked on element like trophies on ps3 do.
Also, I like that achievements are actual points and available in almost all 360 games since the system's launch.
Achievement points imo are the greatest advantage the 360 has over the other consoles.
Ps. I also like achievement locked and unlocked logos. They remind me of this:
