Summary: I got this lens because I wanted something to compliment my sigma 17-50. That lens is so sharp and I love it. I do have a 60D and since it is an APS-C sensor, this lens is made for my sensor. The price is high but you do get what you pay for. The housing is sturdy, the lens is a constant 2.8 aperture and the OS works great. I sold my canon 70-200 f4L (non IS) to help fund this lens and I will say this lens is sharper. I wouldn't see any one being unhappy with this.
Summary: This lens is a bit unusual. One of the features that DX shooters often like is the fact that they get a bit more reach than full-frame cameras from the same lens. The classic 70-200 lens has been common since the film days as a usable telephoto range. It carried over into the DX digital market with the attraction that it now operated more like a 105-300 zoom thanks to the focal magnification factor of the DX sensor.
Summary: Can't beat this lens for the price. It takes sharp photos and distortion is minimal. There's also a profile for it in DxO Optics Pro, so correction is easy. The image stabilization is superb - considerably better than the stabilized 18-200 Nikon I use as a walkabout lens. While I might have slightly preferred a 70-200 focal length, the price difference wasn't worth it for me.
Summary: The only con I have for this lens is the size but the IQ more then makes up for it :) It took me a long time to decide get this lens, I have the older 50-150 hsm II that I have used for a few years and thought it was a good lens. I was not sure about the increased size but after more then a few very good reviews I pulled the trigger and I am very glad I did. I find the focus on this lens to be very good, it works great every time.