I bought the lense and it's my first long range lens. I've taken quite a few pictures with and have only have two complaints, but they aren't really about the lens.
1. I like the 6 year warranty, but I don't like the hassle to register and get in the database from Tamron for the warranty.
2. When I purchased it I contacted Amazon to find out if the lens caps were in the box and was told the front lense cap wasn't, so I purhased the lens, cap,and Tiffen filter as one purchase. Well, I can tell both caps and the lens hood were in the box, so I'm not to happy about buying an extra front lens cap.
Overall I beieve this is worth $164 dollars for what you get included with the lens. I'll be considering Tamron lenses when I make my next lens purchase for my Sony A55.

Update 12/29/2012
I used this lens to take quite a few pictures now and I expected for the price there would be a compromise, but I've yet to find one. I'd say this is worth the price for the photo hobbyist considering the same/or like Sony lenses are much more expensive. I had a chance to try a higher priced 70-300mm lens from Sony and it did not take a better picture.
I bought the lense and it's my first long range lens. I've taken quite a few pictures with and have only have two complaints, but they aren't really about the lens. 1. I like the 6 year warranty, but I don't like the hassle to register and get in the database from Tamron for the warranty. 2. When I purchased it I contacted Amazon to find out if the lens caps were in the box and was told the front lense cap wasn't, so I purhased the lens, cap,and Tiffen filter as one purchase. Well, I can tell both caps and the lens hood were in the box, so I'm not to happy about buying an extra front lens cap. Overall I beieve this is worth $164 dollars for what you get included with the lens. I'll be considering Tamron lenses when I make my next lens purchase for my Sony A55. Update 12/29/2012
I used this lens to take quite a few pictures now and I expected for the price there would be a compromise, but I've yet to find one. I'd say this is worth the price for the photo hobbyist considering the same/or like Sony lenses are much more expensive. I had a chance to try a higher priced 70-300mm lens from Sony and it did not take a better picture.