I had this lens for about 2 months and got tired of it. It sucks at focusing in low lighting (I started shooting weddings and need accurate focusing indoors). I might have had a body copy but it isn't very sharp at 2.8 even with post work. I found it acceptable at 4.0. I may have a bad copy though. The bokeh at 2.8 is great even when stopped down the 7 aperture blades look fine if you aren't scrutinizing your bokeh. For the price, this is a great lens, its small, inexpensive and I would recommend it to anyone who wants something similar to the 24-70 L but doens't want to drop 1k on a lens. (get a flash... photography is all about lighting anyways)
I upgraded to the 28-135 f3.5-5.6 i lost those stops in aperture but I gained IS, USM, and a longer range. the tamron is sharper than the 28-135 at all stops and focal lengths as far as I can tell. But IS, accurate/quiet focusing and that reach is important to me.