Yes, it's a good deal. I used to shoot with a 16-35, but sold it for a 17-40 since I never shoot wide open. I don't miss the extra stop one bit.
I used to own f/2.8 glass, but not anymore. Since I rarely aim for shallow DOF and with the incredible high ISO capabilities of modern DSLR's, fast glass is simply a luxury I don't need. Then Canon comes out with a new 61-point AF system with 41 cross-type points that are sensitive to f/4, which makes owning f/2.8 glass even less important. The f/2.8 glass does make your e-wang look bigger, though, but I don't have a sig to list my gear in anyway
Different strokes for different folks. If I were a bokeh addict, I'd just pick up a really fast prime.