Here's some sample photos with the D810 + 20/1.8G. All shot here handheld.
I'll say the 20mm f/1.8G is not as sharp as the 35mm f/1.8G, and on par with the 28mm f/1.8G only at f/2.8g onwards. But I've to find some time to AFtune this lens and run it through more..
All shots output from DxO Optics without any lens correction (No profile yet, so no vignet/distortion control)

Random Outdoor test for Nikkor 20mm f/1.8G by darkalfie, on Flickr

Merlion by darkalfie, on Flickr

Boat Quay by darkalfie, on Flickr
I'll say the 20mm f/1.8G is not as sharp as the 35mm f/1.8G, and on par with the 28mm f/1.8G only at f/2.8g onwards. But I've to find some time to AFtune this lens and run it through more..
All shots output from DxO Optics without any lens correction (No profile yet, so no vignet/distortion control)

Random Outdoor test for Nikkor 20mm f/1.8G by darkalfie, on Flickr

Merlion by darkalfie, on Flickr

Boat Quay by darkalfie, on Flickr