Do they remind you of a peaceful ice lake? The Keygeek Mirror Lake switch is one of the newest releases after Keygeek modified its switch molding. The adjustment solved the most "deadly" issue with previous releases which was that both the bottom-out and top-out sound scattered. With the new mold set, Keygeek is now able to make switches that sound and feel solid. The stem wobble issue is also no longer a big concern.
The UPE stem plus PBT+%30 FG bottom housing is an interesting combination since UPE is very soft and PBT+ fiberglass is stiff. They create a sound signature that is on the loud side but not harsh. The UPE stem also buffers the bottom-out feel to make them more comfortable to type with. I usually avoid describing switches in this way but in this case, I think you can call them "marbly".
