Amazing! I already had a set since I owned the FC750r but really wanted another.
Each of the keys are 1.5mm thick, shift keys, enter, spacebar. Quality is unmatched, the keys all have nice clean square edges, not rounded.
I'm on mobile though I have posted some gallery links of pics.
Profile height is about identical to Cherry keys, difference being the shape (squared edges) and if most GMK sets are similarity produced to the 'authentic cherry keys' on elitekeyboards.com than I would say they are better made than GMK's in that each key is 1.5mm thick, whereas with GMK only the the 1u keys are 1.5mm, the others (alt, enter keys) were noticeably thinner (1.1-1.3).
Texture is really smooth but not slick like ABS.
Great value IMO, as mentioned earlier I was thinking of writing a review for the Leopold stating 'buy this board, if only for the keyset!'