I had this lens some years ago (with my D100).
- very solid build
- very sharp, just about at par with the 17-25 f/2.8 (which I got to replace it)
- I found it to have somewhat more pincushion distortion at the wide end
For me the added 3mm at the wide end was justification to get the 17-35 at the time. I tried them side-by-side and one does appreciate the seemingly little difference of only 3mm (especially with digital).
So,
- if you are OK with the 20mm at the wide end, you will love this excellent lens, which of course can be had much cheaper then the 17-35 or 17-55.