I do like achievements, it does help give games more longevity, I find myself trying to get certain achievements and liking my gamerscore getting bigger. Not for an ego but rather self-accomplishment. Seeing 725 points in Bioshock gives me the feeling I really put some effort into the game and got a good amount of playtime out of it. While having some small amounts for games I rented for a few days gives the opposite feeling. (because it was probably shit)
If I had to choose between achievements and trophies, as a concept I prefer trophies. With achievements, lets say you complete a hard challenge for game A and get 50g, while in game B you simply jump 50 times and get 50g, easy and hard task/time commitments having the same value. In the end it's all up to the developers to decide the values. While with trophies they are simply put into bronze, silver and gold (and platinum) bronze being easy, blah blah blah, you all know. That hard task in game B will be gold, and that easy task would be a bronze. It gives a clearer idea into how many hard and easy trophies that person has achieved. Also the level system sounds nice. Now all they need to do is allow your trophies be used to get free Home stuff.



