Upload & Sell: On
You are assuming this is the same lens, which it is not. I had the other one repaired (not under warranty) for about $300, then sold it.
My comments on the new one are pretty well the same. The only advantages the Tamron has over the Canon are: cheaper, lighter, and 100mm more reach.
Tamron AF sucks compared to the Canon and lack of focus-limiter is stupid.
Indeed, I made the mistake of assuming. I forgot how quickly many seem to rotate their stock of gears here. Yes, gears.