My UD arrived several days ago, so I thought I would give a mini-review. I've had a couple other log vapes, several portables, and tried other desktop units once or twice.
My standard-sized standard-core "rustic maple" UD is good looking, and was well packaged.
A small touch compared to other logs is that the aroma cups have a ring of rubber near the top so that you can pick them up without tweezers even when they're hot. There are other nice touches, not worth mentioning on their own, but just know that the details are resolved.
The UD's a little hotter to the touch than my previous logs, probably because it's a little smaller, so the heat has to escape from a smaller surface area, but no part is too hot to hold, so it's nothing to worry about.
I got a mix of nylon and glass stems. I prefer the nylon ones because the bowl is slightly smaller and I prefer to use a small quantity, but with some care I'm sure it's possible to suck just as small of a quantity into the glass stems. (Actually, I use a stem from Ed's TnT. It's functionally the same as the nylon stems, but looks cooler.)
I feel like the vaping temp is slightly higher than on my old MZ, and I'm not sure which temperature I prefer, but both are definitely in the acceptable range. The hits are a little denser, the "burnt popcorn" flavor starts a little sooner, and the abv's a little darker, but mostly it's a similar experience.
Because of the (perceived) slightly higher temp, I prefer not to seal my lips around the stem so that some fresh air comes in, which reduces the density, and therefore lung irritation. This works perfectly so I won't bother with a VVPS to lower the power. If your material isn't as dry or finely ground as mine this technique shouldn't be necessary -- some of the heat will go into evaporating that water. Or, if you're used to combusting, even dense vapor will feel smooth. Basically, what I'm trying to say is that I'm a weenie, so the slightly higher vapor density is nothing to worry about.
Anyway, I highly recommend log vapes, and the UD seems to be a good one. In my experience, the best portables still don't match the vapor quality and ease of use, especially if you want even heating of your material without stirring. The Firefly comes closest, and it still doesn't get there. Compared to other convection desktop vapes, logs are just smaller, simpler, and less obtrusive.
I anticipate that this UD will be my daily driver for the next few years. Cheers.