Well almost a month and a half of me using the Cosmic Case 4 piece 2.75" model.
Zero complaints whatsoever*. Probably had roughly 1oz of bud go through and no cleaning involved at all and still turns smoothly - even better - there's hardly any residue build up on either male or female section walls.
Kief collection has also been pretty on-point, measured just shy of 0.5g before that was devoured for 4/20, and there's been no hints of green in the kief either.
Still fluffs the bud up when used the right-way up, and gets much finer when used upside-down (which I've not been doing).
*Actually come to think of it, I do have one complaint although it's minor. There's a fair amount of trichome coverage on the teeth (from normal use). Honestly it doesn't bother me though - what's deposited on one grind may get picked up by the bud dropping through, on the next grind.
I'll try and get a picture tonight to show the minimal residue left.
Gotta rep' the love for the Cosmic Case - not many people use them - but they're the original SCS & Space Case company so not much can go wrong.