Why does Tameron 28-300 cost $100 more than the Same Sigma
I currently own the Digital Rebel with the 18-55 lens and I love it. I already have the tameron 24-70 that I bought 6 or 7 years ago for my Canon IX APS camera. I also have a canon 75-300 with a bad focus motor. Both were very inexpensive when I bought them so I don't think it will pay to try to get the canon 75-300 fixed. I have been considering getting an all in one lens like the 28-300 so that I wouldn't have to keep changing lenses. When you have a 9 month old daughter you often don't have time to switch lenses to get the shot. I have looked extensively on the internet for both the Tameron 28-300 and the Sigma Compact Hyperzoom 28-300. The cheapest prices I found for either of them was at Adorama. The Sigma was on special for $194 and the Tameron was not on special for $364. They both see to have very similar specs. I can't seem to find any review sites that will compare them head to head. Does anyone have any experience with these lenses and can tell me if there is any reason to spend the extra money on the Tameron.
By the way assuming that I do buy one of these lenses I am looking to sell the Tameron 24-70 and the broken 75-300 lenses. Does anyone have any good places to sell these lenses. Should I try to sell them through EBAY or through one of the camera stores that buy used equipment?
Thanks in advance for any advice