One of the best rubber domes there are, IMHO. This is definitely a better keyboard than any version of Microsoft "Natural Keyboard".
For one thing, it is adjustable. It has some hand separation even if it is laying flat, and I find even that to be a plus. Having PgUp/PgDown/Home/End on the left side is something that you get used to after a while.
My only complaint is that the keys are a bit noisy on the upstroke... but that is still insignificant to any Buckling Spring keyboard.
It is definitely worth $20 including shipping. They sold for more on eBay, the last time I checked.