GlassStones = sharpening on a granite black
Ume 1k = sharpening on a bed of roses and love, mixed with some Barry White tunes.
Although the above is an obvious attempt at humor....it is true for me. Sharpening on any of the GlassStones was not pleasurable at all. They, as I recall as it's been a while now, had better feel than most of the Shapton Pro stone's.....but none had nearly as good of feed back as the other good stones in the same grit.
The Ume 1k has a really great feeling.
The Bester 1200 does as well, but the Ume wins these days.
There are several King 1k and 4k and 6k stones, so I don't know which one's you're asking about. I have a King Hyper 1k that has great feed back....but it's not available any where that I know of.
The Rika is another great feeling stone.
To compare them directly to the Shaptons, though, is seemingly impossible to do in words.