Picked up this lens used in the locals classifieds to add to my full frame kit as a mid-range zoom. The lens is almost 10 years old, but it feels like it will last for another 10 years. I didn't want to dump a load of money (k$) on my new lenses so opted for third party brand, knowing this lens is sometimes compared to the Canon 24-70. For the price paid, I must say I was pretty impressed on the overall build quality and sharpness of the lens, even though it is a bit soft wide open. Contrast is very good too and AF is quite fast.
On the negatives, the lens is a bit noisy while focusing (like an electric buzzing sound), but nothing compared to my previous Tamron 17-50 (I could not support it). I don't
As for the reversed zoom compared to Canon lenses, it didn't bother me at all. As a photographer, I always have to adapt to any situation/lens so you get used to it very quickly. It does not and never bothered me.
I could not be happier with this lens and it satisfy my needs more then expected !