Honestly, my favourite grinder is the Storz & Bickel ones, either the large herb mill or their standard one depending on how much I'm doing at once.
It used to use the old standard aluminium grinders with the kief-catchers and the multiple layers etc, but at some point I failed to see the benefit of separating half the trichomes while grinding and I had the S&B which came with my Mighty and it didn't have a catcher, so I switched to that and to be honest they are great.
They last a long time, they grind up very consistently, you know S&B put their research into the materials from a health point of view, etc, and in terms of stickiness I'd say you just need to use a decent brush/poking tool to get as much out as possible and increase your cleaning frequency rather than invest in some super "anti-stick" technology. A couple of minutes with some isopropyl and a decent brush once a week does the trick.
Unless you have some ideological opposition to plastic (see George Carlin), I recommend it.
Watched some reviewed of the Old Mate one, but people seemed to spend a lot of time like thumping the grinder to get the herb to fall though the gaps into the bottom chamber, which seems like a lot of effort and potentially an injury risk since it's apparently so heavy! And like the kief catcher, I'm not really sure what the point of the 2nd chamber is. I guess it's a way to standardise the courseness of the grind since the falls through when it reaches the diameter of the holes, but I reckon the courseness of the grind is one of those things can be quite personal and depend on your device, etc, so I like with the S&B that there's only one chamber, and you decide your own courseness just by how much you choose to grind.