8 out of 10 points and recommendedCheap, light, fastPlastic feels cheap, noisy focus
I previously reviewed this lens and was unhappy with the sharpness, speed of focus, focusing noise, and the number of times it would focus inaccurately. I have since purchased the 50mm f/1.8 and the 17-55 f/2.8 lens so can better compare these lenses against the Tamron.reviewed September 10th, 2008 (purchased for $300)
My perception that this lens was inaccurate at focusing was mostly due to my lack of experience with fast lenses. I have a harder time getting accurate focus with the f/1.8 lens since the depth of field is so small. The 17-55 f/2.8 has less occurrences of focus hunting than the Tamron and is slightly sharper, but you pay for this in weight, size and cost of the lens. The noise of the focusing is still an issue of this lens, as is the cheap feel of the plastic.
Over all this is great value for money and so much better than the kit lens! If you want fast, light and cheap, then this is the lens for you. If you don't mind weight and cost, then go for the Nikon 17-55 f/2.8. If you want absolute quality and don't need the zoom the 50mm primes produce the best results.