I've been looking at getting a sigma 70-200 f2.8 for a while now, and now that I just got a new laptop, the lens is next on my list of things too get. Was going to wait until the end of the summer but I'm getting very irritated with my kit 75-300mm Sony lens. B&H had been out of stock for a while and listed their expected arrival as August, so I went on Adorama and to my complete shock, they listed the Sigma at $1699!!! I went to Sigma's website and even they listed it at around 1600?! So I went to B&H's site just to check and they did have it back in stock at the price I was expecting of $799. I did discover that the manufacturer part numbers were different B&H listed the Mfr# as 579205 while Adorama listed it as 589205. The only thing I can conclude is that Adorama has a newer version, but I can't imagine a new version being almost $1000 more, I can get Sony's version of the 70-200 f2.8 for that price. which I wouldn't because I just spent $1800 on a laptop and there's no way I'm going to spend another $1600 on a lens, I can justify that amount when it's for a laptop that I use constantly for school, and at home, but not for a camera lens when photography is just a weekend hobby for me. What could possibly make the new sigma's worth so much more? I thought the only reason people really bought the Sigma and Tamron 70-200's was because they were basically half the price of the Sony, Canon, and Nikon equivalents?