For me? Horn is more slippery, unless one buffs it a bit with some #000 steel wool, in which case it's fairly grippy but not as attractive.
It rains a lot around here. I'm usually stuck out in it. They're both slick in rain. Horn is a bit slicker unless it sees the abovementioned buffing.
I haven't had cracking with either, but then again, I'm still at the two month mark. (The antler has not been, and probably never will be, outside.) The wood used to get boiled linseed oil on the traditional schedule: remove the original wax and drive out the remaining oil, re-oil several times until the grip stops absorbing it, then once a day for a week, once a week for a year, once a year for life...same thing as my gunstocks and on the same schedule. I've since switched to Ballistol. The grips get oiled when the blades do...once or twice a week, or when I feel like it, or after use. (The scabbards get oiled along with them.) This is far more than what is necessary, but I'm used to lubing guns once or twice a week and the khuks went into the rotation. Once a month, or just after use, should be more than enough. Also note that, for me, red/flaky rust (and pitting - especially pitting) is unacceptable but tarnish or patina is fine...that's the working man's bluing.
The local feed and livestock shop didn't have Hooflex. (They have electronic mousetraps, they have tarantulas, but they don't have Hooflex.) Satori's Special consists of: one jar of hydrous lanolin from Walmart, enough turpentine to dissolve it while its container is sitting in the hottest water the tap can produce, and a couple of tablespoons of neets foot oil. No cracks, smells nice, and polished horn handles stay shiny. Once every two weeks or so the handles all get slathered in the stuff with a small paintbrush. (The military "acid brush" is perfect for this.) I let it sit for an hour or two, then wipe off the residue and buff with a rag. Everything's nice and shiny afterwards. I try to hit the exposed metal on chiruwa style grips with Ballistol later, but even when I forget, the metal doesn't seem to rust or tarnish. Similarly, if I happen to get Ballistol on the horn, it doesn't seem to hurt anything. (It probably helps.) This seems to be working for antler as well. The figure of the horn appears to improve over time with this treatment and I'm now seeing a bit of grain in the "grainless" handles I had. The one gray horn handled khuk I've purchased went to a friend as a Christmas gift, but if and when I ever do get one for me, I can't wait to see what this will bring out of it. I personally think that gray horn is far more beautiful than either regular horn or non-exotic wood, and is tied with antler.
If it's a UBBB, I'll take what I can get.
Also, if I'm buying off the website, I opt for whatever the description lists as "mostly" - I figure it eases logistics on the Reno end and speeds up delivery. They're both nice. They're both beautiful in their own way. They're both under warranty. They both get wrapped up in paracord if they don't fit my hand.
If I had to choose? Horn, just because it's very unusual in this part of the woods. Other than that, either one works for me.
