This is an amazing lens, this would probably be in their PRO line if that line existed when this lens came out. The only improvement I'd like to see is weather sealing. As far as sharpness, it's one of the best lenses out there.
spencerberusagreed. weather sealing would indeed be nice to have...this lens is sharp with beautifully blurred backgrounds, about as best as it can get with this sensor size...