Strengths: I find the strong cousioning on the heal very good, which I felt the 2090 had but the 2100 did not. The support in the middle of the foot has improved so much and the front is still as good as ever.
Weaknesses: Sounds very small but I have found that the shoe laces are not long enough!! So have transferred my old ones from the GT2100.
Overall: Done about 25 to 30 miles in these now, over 2 runs and am very impressed. The support they provide for the whole foot and shock absorbance from the road are brilliant. They have put back in what I liked about the 2090, that was removed from the 2100 and improved the middle stability