Great Lens!
I took an egg away for the somewhat slow AF and lower image quality (Compared to the Canon). Don't get me wrong though: If you use stabilization a lot this is an excellent choice and bargain! The image quality honestly is quite good (just not as good as the Canon).
Vibration Compensation works great Fast 2.8 Accurate Auto-Focus (on my Canon T3i
Not as good image quality as the Canon 24-70 2.8L II (but close; I think it is at least as good as the Mark I) Auto-Focus seems slow, and not accurate good in AI Servo $1000 or so less than the Canon