I haven't tried the 16-35 but I will say the corners on my 17-40 are terrible. When your at the wider side of the lens, the corners are filled with chromatic aberration. When I was shooting on crop, it was a great lens but now it definitely falls short of expectations. I've had to crop some of my photos taken at 17 (even stopped down to f/11 or greater) because the corners were unusable. This maybe just my battle torn lens needing some realignment sense the bottom left corner is the biggest problem.