I decided to try out Nether from yesterday's sale. It's another survival type game in the mold of DayZ, except a little more supernatural. I first have to admit that I haven't played DayZ in its alpha standalone version, just in the mod version... and that's probably been almost a year ago. Still, my thoughts on it...
Nether though feels much more like a traditional FPS. You start off with a melee weapon, compass, and map, sometimes there are surges that you can try to defeat with other people. Of course, most other people will just shoot on sight, so that doesn't happen often in my experience. It's much easier to find guns, and there's a single combined water/food meter that represents all of your character's needs. Day/night cycles are much faster, and (currently, though it's set to expand) the map is much smaller. I did like that there was a variety of NPC enemies, instead of all the same type of zombie though.
DayZ is (or was, when I played it) more jerky, and I always thought it was pretty obvious they were trying to shoehorn in a game into an engine that wasn't designed around that sort of play... though hopefully that's changed by now with the standalone. It just feels more realistic in a lot of ways. When I ran out of food and water in it, I was always legitimately scared I wouldn't find anything in time. I needed to decided if it was worth going out for supplies in the rain. It just really felt a lot more tense. It wasn't perfect either though - there were basic failures like getting constantly stuck trying to get in and out of a building, or not actually being able to tell which buildings you can actually open the doors of, or that sort of thing. And one huge thing that Nether does better, is that DayZ's world often (but not always... depending on where in the map you were) felt like a normal pristine countryside setting, whereas in Nether, the world immediately feels apocalyptic.
Personally, if I was going to pick between the two, DayZ was better even back in mod form. Still, Nether was pretty good for the hour I played it, and for those who prefer a traditional shooter, it feels way more like that than the Arma-based DayZ does.
Of course, like I said, I haven't tried the standalone DayZ, and both are in early access right now anyway, so either could possibly change dramatically still.