I've personally never had a Gaomon since my tablets have been a Wacom or a Huion (my current one); the latter being a gift from Christmas. Both of them have served me well but I do prefer my current tablet since having those buttons for shortcuts is quite handy.
I bought a Goamon M10K a few months ago for ~61€, I have no complaint about it. I wanted a low price tablet to start with, rather than buy an expensive one and maybe quit using it.
I am quite happy with the number of buttons (10) even if I would like to fit maybe one or two more, but I saw some higher priced tablets have less buttons... Lol
I haven't spent years with it yet so maybe I am not aware of its flaws, and it's my first tablet so I haven't had the chance to compare it with anything else ^^"
Ah, and also, the Gaomon M10K doesn't have an embedded screen. I thought it would bother me, but in fact it doesn't, and for posture it's better to look at your computer screen rather than your tablet.