Actually I owned the 17-35mm f2.8-4 Tamron and 18-35G. I prefer the 18-35G and it's quite sharp, sold it because underutilized.
For best review, I normally wait for DD advice. Haha
I owned the 16-35, 18-35g, rented the nikon17-35/2.8. They all have their uses. I stuck to the 18-35 mainly for the size (I like to keep a wide lens in the bag when i travel, just in case)
And yes, DD's advice are words of wisdom and not just numbers