Upload & Sell: Off
Maybe a tiny bit of purple on the clouds in the upper right. But not enough to bother me. I think the story might be a bit different with the 7, though.
(on a positive note, I used the 16/2.8+UWA on the 7 yesterday for the first time since the firmware update. . .and had no purple-corner issues at all. Can't see one bit. So, maybe the 7 will do well now with the 10-18 too?)
Overall, looks like a pretty sweet lens. The pricing is in line with a constant-aperture super-wide zoom IMO.