I'm very interested in this lens as a replacement for my 70-200/VR. Two issues are holding me back though. Is it sharp wide open? Some full resolution samples at different focal lengths would be very much appreciated. Every shot I've seen with this lens seems to have a bit of a purple/blue tinge to it, especially skin tones. Anyone else notice this? I'm very particular about rendering, so this is a major issue for me. I like everything about this lens: range, HSM, decent build, size & weight, pretty much everything else. I just need to overcome these two issues to pull the trigger. The Tokina is a distant second choice, but from what I've seen, it renders clean and completely neutral colors and is sharp wide open. So I might end up compromising just about everything else to get those two qualities.