I have added a few comparison shots of 17-55 vs 17-35. The new lens seems particularly sharp at the long end. All medium jpg, converted from NEF in NC4.1, in camera (D1x this time) sharpening set to normal.
http://www.pbase.com/ibbo/17_55mm_dx
My 17-35 is now over four years old, and the zoom has got quite stiff, so the new lens inevitably handles better: no observable weight penalty, though I will have to watch the amount of air it sucks into the mirror box (like other high ratio zooms).
pi