Some great points made so far. I'd like to add some observations.
The palm rest on the MSNEK4000 is the most comfortable palm rest I've used on any keyboard. There is a soft, springy sponge pasted atop the moulded plastic rest, and that is covered with a soft faux leather (velour?) sheet. The combination of the materials and the shape/height/angle is exceptionally well designed.
There are those who say that resting your palms while typing is bad for you. Indeed those who attended touch typing courses know that hovering your hands and fingers above the keys is considered good technique. But this keyboard proves that it can be comfortable to touch-type while resting your palms.
One of my biggest gripes with legacy keyboard layouts (that's 'normal' layouts to most people) is the asymmetric reverse-stagger. If you're touch typing, the left hand adopts a twist towards the left that can cause aches and pains when typing for longer periods.
The MSNEK4000 actually reshapes the keys on the left hand side to compensate for this funky reverse-stagger, look at how wide the tab key is, this encourages a tilt to a better natural position for the left hand*:
This keyboard is aimed at working touch-typists and is designed to allow them to work in comfort - certainly with more comfort than a regular office keyboard.
So quickly referring to Dictionary.app on MacOS:
"Ergonomic: relating to or designed for efficiency and comfort in the working environment"
While I think the efficiency of any given keyboard shape, layout, switch etc. is immeasurable, I think this keyboard is certainly designed for comfort. By that definition, it undeniably IS ergonomic.
* Incidentally, I don't think MS went far enough with this correction of the left hand stagger, this is one of the reasons I started investigating
the Katana layout.