About me: I consider myself a well-read enthusiast with the budget to revive an old hobby from the 35mm darkroom days. I bought this lens after reading and seeing many recommendations for this particular 70-200mm format also available from Nikon, Canon and Sigma. According to other reviews, Tamron does not lag behind analogues from Nikon or Canon, it is better than Sigma and cheaper than the first two manufacturers mentioned above. So, while I can't compare, my observations are as follows: All cameras I've had in the past have been used with a kit lens (read: cheap, small, and light). To be honest I was shocked when I opened the box. This thing was intimidating and it weighs accordingly. Personally, I can handle the weight and appreciate the calming designs, but I don't see my wife taking it to the playground. Taking notes on a piece of paper with a pencil is like lugging a typewriter into a lecture hall. People notice you with it. I use it on a Nikon partial frame DSLR. I decided to spend the money on glass (which will keep its value) and invest in a better camera if my interests continue to warrant it. The lens is fast, focuses well, its internal movement is almost inaudible and is great for photographing moving children - assuming you can take the weight. Portraits are fantastic and the lens is incredibly sharp when you focus. I recently photographed a parrot from 15-20 feet indoors without a flash and you could see the folds of skin around its eyes. Feathers were rendered well with no aberrations, colors were accurate, and bokeh was nice and soft. I bought this through Emmy, assuming that the lower price and 3rd party warranty would get me a gray market product (although it wasn't advertised as such) and was not disappointed in my assumption. However the lens arrived at NIB, works well and I've had no problems, I'll have to think about what to do with it when I get back from my trip.