8 out of 10 points and recommendedPrice / Performance is outstandingBuild quality is not great
I am a pro shooter (yes on the DX format) and needed a good wide-to-normal zoom for assignments. I often work in crowded environments and my gear gets banged up a lot. I like this lens well enough that I own 2 of them as I seem to often have one of them in for service. Image quality is very-good to excellent. I like the image quality so much that I do recommend this lens to friends that are occasional photographers and they tell me it's their favorite lens.reviewed August 9th, 2010 (purchased for $479)
This lens is very similar the Nikon 17-55mm but at a fraction of the cost. I don't see spending almost 3x the money on the Nikon version jus to get a little better build quality. Besides, for as often as stuff breaks do I want to own 2x $500 lenses or 2x $1300 lenses.
The build quality seems weak. The plastic doesn't bother me, rather things like the zoom ring spinning around 180 degrees and the reduction in the quality in the autofocus over time bothers me. Keep in mind that I also shoot 50-80k frames a year - I'm brutal on gear. Maybe I'm wearing out the autofocus motor? Most people won't.
I am not crazy about Tamron repair service. Nikon service may be very slow but it is good. I've had to argue with Tamron (actually the local store does this on my behalf) about some repairs where I felt it was their problem - I have no issue telling them when I broke a lens, I've broken them a few times, but when they argue about the focus ring being spun around I had to take a stand. I'll note I didn't have to fight them the second time it happened.
Overall I give this a solid A rating. Most folks will like this lens for it's great images and they won't use it up nor complain about build issues as I do.