NixOS is one of the few distros that legitimately offers something different. Some nice things:

• The entire OS install is managed through config files, so instead of dealing with a billion shitty DSLs, you only deal with one.
• Because of the above, builds are also reproducible.
• Because it ditches the FHS for the Nix store, you can do things like install multiple versions of the same library side-by-side, which is impossible with traditional Linux package management.
• It has the largest package repository of any Linux distro.
• Setting up dev environments is really nice because with Nix it's like the entire OS has VirtualEnv.
• Because of the above, "it works on my machine" is an excuse of the past.

It's very impressive and is a welcome innovation to the Linux ecosystem. Now if only they could improve the tooling and documentation.

"Seriously, NixOS is the new Arch when it comes to telling people you use it" ...as an Arch user, I feel both attacked and intrigued.

But seriously, it's pretty amazing how far the community has come now that having to use the package manager through the command line and editing config files is considered a significant barrier to entry. I'm interested to give it a try to see if the purported advantages with respect to reproducibility and portability are actually robust enough to suit my own use cases.

NixOS base + flatpak for Desktop apps sounds very interesting, one of the Linux Unplugged podcast hosts have been doing that setup for a while now, they also had a NixOS challenge some months ago