These keycaps look great. I had been looking for modern looking dark keycaps for a few months and when I saw these I settled for them.
In term of color it's not pure black but more like dark gray which was not super clear when I bought them but they look great on my black Keychron Q12 HE anyway. I have a silicon wrist rest and they match the color of the wrist rest more than the chassis of the Q12.
I also purchased the numpad kit for which I was just a bit disappointed that the 5 key had a bar when the photo on the seller's website showed none and that the regular base kit has F and J keys with no bar. But this is just me nitpicking.
In term of sound I don't have much experience with high end PBT keycap sets so I can't really compare, but they sound rather high pitched. Also the space bar rattles a bit which wasn't the case with the default keycaps of the Q12. I added some foam inside it to reduce the rattling but it deserves to be mentioned.
Finally in term of price I think that they are quite expensive for what they offer, especially since they are just dye sub and not double shot keycaps, but overall I'm happy with them so that's a 4 out of 5.