8 out of 10 points and recommendedprecise focus. well built. vibration compensation. sharp. excellent bokehnon I am aware of.
I had a chance to test this lens on my 5d m2. I compared it with the canon 24-70 ver 2.reviewed May 31st, 2012
Autofocus: Canon is twice as fast(probably because there was more light in the Canon's stand) but it's not precise. The Tamron nails the focus every time.
Build quality: They both feel well built, although i suspect he Canon should be better built. I like the feeling of the Tamron better.
Bokeh: Amazing! I don't know why some people complain about it. This one had no problems at all. The Canon bokeh was more like Gaussian blur...
VC: The Tamron is the only 24-70mm with VC.
Zoom and focus rings: Soft and accurate. Both lenses have full time AF overdrive.
Optics: Very sharp. The Canon is 1/3 sharper and has better resolving power. I wouldn't use these as portrait lenses. They are TOO sharp(with Canon having the lead). Not recommended for people with skin other than perfect.
Price: 1200$ VS 2400$+ Absolute bargain!
I have this lens on pre-order. Arriving in 1 week. I will make a better review then.