I’ve been sitting on this review for a while now, but here is my in-depth take (a little over 5,700 words) on the GMMK Pro after 2 months of use. I purchased the keyboard with my own money in the first pre-order batch.
Hope this is helpful for someone out there, and feel free to let me know if you have any questions or feedback as always! 
I loaned mine to a friend and he liked it so much that he’s going to get one for himself. So it’s definitely not a bad board.
I do find I like the sound of it with the brass switch plate and all the foam for what it’s worth. I also really don’t have any complaints about their stabilizers. I added some additional lube to them, that was about it.
Interesting point about the stabilizers – I wonder if certain batches were manufactured a bit better? The spacebar rattled an insane amount even after cleaning and relubing with 205g0.
But I agree, I don’t think it’s necessarily a bad keyboard. I just wonder if I would still recommend it to friends if there were another option in this space.
Yeah, I really don’t know. I could also have ridiculously low standards too. 
I honestly wasn’t trying to recommend him the GMMK Pro, but among the six or so keyboards I showed him, that one impressed him the most. He’s never going to want to use QMK or Glorious’s lousy software to customize it, so from that stand point I think he made an decent enough decision.
At least from a Grams per dollar perspective.
Ah yeah I think one of the points I tried to make in my review is that the GMMK Pro will make a really good first impression on someone who’s never tried a custom keyboard or even a mechanical keyboard before.
(And this crowd wouldn’t have enough context to care about the nuances of a stiff/soft typing experience or acoustics either).