Like bram said the big difference is the braking, with gtr2 it was just too easy to brake late and keep it all together.
I do miss the tyre choice that you had with gtr2 and some of the gt cars in evo are just a bit to easy to accelerate with as if you had traction control always switched on.
If i had to choose then it would be evo every time and not just for the above because for me the biggest change is the online collision detection in race07/evo is far superior to gtr2 and makes it so much more realistic to drive.