In short, I’m a bit torn- in many ways, this is my dream lens. It’s light, small, and doesn’t cost $2,000. (I’m looking at you, 14-24!!!!) Oh, and those sunstars!!!!
On the other hand, the corners could be better. The coma and vignetting is just a tad disappointing, considering the price. I might not have complained if they had priced it at $600-700, but at $800 I’d have liked to see just a tiny bit more. Not because it’s really that bad, but mainly just because I know a Sigma 24mm f/1.4 Art is probably right around the corner, and it will probably have far better performance in the corners, plus it will have f/1.4 instead of the f/2 that the 20mm is in real-world use. Lastly, a Sigma 24 Art will probably cost “only” $900-1000.
So, take your pick. Wait and see what Sigma does in the next 6-12 months, or wait and see if Nikon offers a $100 rebate on this new 20mm f/1.8 G in the next 6-12 months, …or just order one right now and go out and play!!!! :-D