UPDATE 4-28-2021: I have tested re-lubing some of the switches using 205g0, including the ones with stems that would otherwise bind. Re-lubing seems to help out a lot with feel, and I personally find the sound signature much more appealing than with the stock lube. I've also discovered some switches had next to zero lube on them at stock, which is kind of odd. This switch is more work than it should be so far lol.
UPDATE 5-7-2021: attempted to use switch films: DON'T! In my example, the switch film caused the bottom housing to be compressed so much that it was pinching in on the slide rails of the stem, creating even more drag than they already have. Also lubed the Gateron Red stem-swapped switch with some 205g0: the switch is downright nice, sound has more character and "pop" than the PC stem did. That's the cost-effective play here: Gateron Red or Yellow stems with 205g0 and you've got yourself a damn nice linear switch.
I have not gotten to test these in the GMMK Pro they are destined for, but straight out of the box these had inconsistency issues. Four of my stems in the 62 g 110 count pack I got were so tight in the top housings they wouldn't actuate correctly and felt heavier than intended; the rest are "usable" in that the stem doesn't bind, but I will need to redo the lube at some point. They would also stick in the top housing and not fully rebound back to resting position. Disassembly revealed that the stems are dip-lubed: this is evidenced by the discovery of lube on the inside of the stem legs as well as the outside, and there being a line where the lube ends at the same spot on the legs and stem of the switch. Some stems have more lube than others, and some actually have lube on the rectangular portion of the stem which can help combat stem binding if tolerances allow for it.
Experimenting with different stems told me some more about the switch: the leaf is FAR too soft and light for a tactile stem, and if you do mess with the leaf be very careful handling it as I permanently warped one of my leaves during this experimentation (totally my fault, got clumsy). Swapping to a Gateron Yellow or Red stem with no lube other than what was left on the housing and leaf resulted in an extremely smooth switch with great acoustics and feel, plus an eye-catching JWK-like appearance. Moving the PC stem in to those same known-good Gateron housings resulted in the stems binding, so the issue is definitely the stems having tolerances far too tight between the top housing and the stem body.
The spring lube is great for all switches so no need to fuss there. The PC housing has some of my favorite housing acoustics I've encountered yet, so it's sort of a shame that the switch couldn't be offered without the stem bc everything else there makes the perfect recipe for an amazing linear switch. When the stems DO work correctly, there is almost zero stem wobble, hence the tight tolerances there... but they need to be more consistent with the tolerances being that tight on all switches.
My recommendation: if you DO choose to buy these, expect to need to work on these a bit to get the switch feeling great, up to and including swapping stems. If you aren't a tinkerer like I am, and want your 60 cent + switch to work properly out of the box as it should, then I would say this ain't it until they get the switches feeling more consistent. It's not likely you'll have a TON of switches that aren't usable if you do have issues, but that doesn't feel great at the price point.