I wouldn't necessarily say there isn't a large following, but its definitely NOT that of the PRC cartridges. It also depends on what circles you run in and who you ask. They aren't a particularly popular here on RS but are in other forums. Mostly because we've learned by now, that you actually don't need ALLLL the ponies, especially if you value shootability and consistent accuracy at distance.( because recoil is a bitch) The 22, 28 followed by the 30 are probably the most popular of the line. Nosler definitely screwed a lot of things up when introducing them. I will say of the Nosler line The 26/27 seem to have the moniker of very finicky/less prone to be accurate, which in term does make those two not very popular in what I've seen.
Do remember sample size of 1 here.
They definitely have their downfalls.
Expensive to shoot(as most overbore stuff is)
LOTS of recoil for small gains
Poor ammo choices/availability
Low barrel life.
That being said I have a 28 built on a defiance. It is super accurate and is a riot to shoot, albeit I will NOT run it without a brake or can, but it is not my primary plinking rifle. It has one job. Elk hunting, because I've shot enough deer/antelope with it to know it kinda makes a mess of shit. Pushing 180 gr bullet @3200 fps is kinda hard on stuff but rather satisfying. Its like owning a sports car or a turbo snowmobile. Very unnecessary but really fun.
My other plinky/hunting rifles in 223 and 6.5 saum are built to ergonomically be like it.
If I were to build/buy a rifle today would I choose a 28 again? NO, I wouldn't.
However I'm not even a little sad about the one I have. When I built mine I bought enough ADG brass at a screaming deal and several hundred bullets and pounds of powder with the intention of it lasting me the rest of my life with a few rebarrels figured in. When I comes time to spin up a new barrel I'll decide if i want to stay with the 28 or sell my components and move on.
So to make a long story short, sure they aren't SUPER popular but I feel they are a long ways from being obsolete. I wouldn't be scared to own one, but there are better choices out there.