I can only speak for the early SLX 303 grinder which I've had for.....it's been so long now I really don't know, but the ceramic coating on mine (only the inside is coated) still looks like it's brand new (I believe it's Cerakote?) and has never accumulated any buildup, residue or visible wear.
However I DO have to clean the anodised interface between the lid and lower grinder part, as it DOES stick eventually, despite the "Never sticks" legend engraved on the base.
My BCG is definitely smoother to turn while empty, but there's little difference while loaded/clean (caveat: I'm a micro doser, and the SLX 303 is a larger grinder than the BCG, so I'm usually grinding quite small amounts in both).
There's a much bigger gap between the lid and lower grinder parts of the BCG than any of my other grinders. I believe this is deliberately engineered to avoid trich's getting mashed between the two components and becoming the sticky 'plaque' that plagues other designs (maybe the castelated teeth around the upper edge of the lower half also play a part, but my belief is that it's mostly simply the looser fit of the lid), and it works. Or at least it has worked for me so far (I'll have to use the BCG for a few more years to be certain!).
I also think the material/manufacture of the BCG glide-ring is the best/smoothest of any of my grinders, and that also promotes a super smooth feel while empty (again, this advantage is less apparent when the grinders are actually loaded, it's still perceptible, but much less so in my experience).
Threadless on the BCG is great, and comes apart a tiny bit easier than my Pucc ( BCG is smoother to turn than Pucc, and I can tell the Pucc will need occasional cleaning around the lid/lower grinder interface just like the SLX and cheapo types).
I do think the BCG looks like it's going to be the best grinder I own, but it's not so far ahead that I'd be happy to pay double what I paid for the SLX, or for the Pucc for that matter.
I still want to be able to just dump the whole grinder in some PBW to clean though so I'm keeping an eye out for the full stainless BCG, or perhaps a Herb Ripper or United Machining model if the SS BCG is beyond what I can afford.
Whatever I go for I'm certain I'll have to sell my existing grinders to afford it.
I really prefer PBW to ISO for cleaning stuff for environmental reasons, and safety (not much of a concern mind you, but still..) and ISO isn't always available to us all, so an all stainless version is my preferred 'grail' grinder be it BCG, Flower Mate, Herb Ripper or whatever.
I was also considering the newer SLX, as perhaps the all-over ceramic coating would resist PBW soaking, but
@LesPlenty's experience with the purple dust put me off, and I'm uncertain about the Cerakote/PBW thing.
There's always the "Steely Dan" all stainless grinders available from Verdampftnochmal which are nice and cheap, but they have threads (and not even half or quarter turn threads like the SLX/HR et-all).
Still, I'm happy with the BCG for now.
Edit:
Oof, sorry for the wall of text!
