I bid on this out of curiosity, as I already have the Tamron 35-70mm f3.5 (17A) version. The starting bid was quite low, but I actually won the bidding, and it went for £13.99, including P&P, so I was quite pleased.
I always check the forums before actually bidding on any lens, and the general feeling was that optically, it was great, but its construction made it look cheap. They weren't wrong there, as it looks cheaply made and feels plasticky, not something you would expect from Canon. I've included a couple of shots with it mounted on my OM-D E-M1 II and in a rare appearance without the HLD-9 Battery Power Grip.
The lens looks good on the camera, the large focusing ring is easy to use and rotates the front so the use of a CPL filter practically useless, but the heavy ridging looks cheap, the zoom ring just below it has the same kind of ridging, and when zooming, it doesn't shrink or extend the lens length. Annoyingly, it moves the elements internally. If you have a clip-on lens cap, it will fall off when zooming from 70mm to 35mm, and to reattach it, the lens must be zoomed to 70mm.
You can of course, add the cap to the lens body itself, but then when you zoom to 70mm it gets pushed off.