This is the lens I was planning on buying, it is an EX model with the new HSM AF motor that is supposed to have better focusing. Im finding that reviews are too hard to judge by, yesterday I was set to buy the sigma after reading a few rave reviews but then the review above makes me question it. It seems like for every good review for Sigma there is a good review of Tamron. I see good shots from both when i search flickr, its just too difficult. The other problem is, my local camera store doesnt carry much in the way of lenses and ive always been pretty disappointed with their service, so trying the 2 against each other is probably out of the question.
Also,
here is the review that helped me decide on the Sigma vs. Tamron. There are some good concrete points that made me decide on this lens. If you Tamron owners disagree let me know why, it will help me make a decision.