I just got is lens, opened it 2 days before Christmas. I am blown away. It is sharp sharp, and lots of good contrast and color. I really like the 35mm field of view too; a lot more than I even thought I would.
Made one dummy error though. I was doing the post processing on my kids opening the gifts from Santa and I noticed some hellacious vignetting in top right and lower left. I was thinking I'd made a big mistake, and thinking how I might have trouble returning it because I got it grey market for $760. Then I thought about the lens hood. Sure enough I had not screwed it on all the way, and the longer petals were on those 2 corners, and not on the top and bottom like they are supposed to be. Problem solved. Duh.