This is what Matt Damon had to say about James Bond.
And I find it hard to argue with him.
Not to mention that Bourne films are just faster, slicker, more believable, and by and large more enjoyable.
It also bears mentioning that I'm biased towards Bourne because I read all the books in my teenage years, when my imagination was at its highest and finest. ;) Bourne was and is my ultimate spy, and the films didn't let me down.