Can anyone talk to if nixos can reasonably be used to run a desktop setup?
After I gave up on the idea of preserving an existing Linux install (that used a file system, namely, btrfs, that NixOS's installer does not currently handle), and just allowed NixOS's installer to nuke my block device (i.e., my "hard drive"), it was easy for me to set up and configure my NixOS install to my liking -- and I know very little about Nix and NixOS although I consider it worth learning, which probably greatly affected my attitude, which has historically had a large effect on whether I succeed or fail at sys-admin-y tasks.
Where the learning curve gets very steep is when I tried to build something from source code! I would've liked to have built Emacs 24.4 from source, because that is the version against which my Emacs Lisp code is tested, but I gave up. (I'm using Emacs 26 instead and spending time adapting my Lisp code -- something I probably never would've needed to do if I could've built 24.4 because I am moving off of Emacs.)
If you're using x86_64, there are tens of thousands of packages with pre-built binary packages, so it might be you never have to build something from source to get the desktop environment you want.
Sometimes it shines ex:
I messed up my x11 config as well as drivers and just booted into the previous generation like it was no big deal
I needed to install a version of electrum that was only available on a specific git commit. I just specified the commit and booted into a shell with it
Sometimes it sucks:
Learning to package arrive 3rd party software can sometimes be really complicated and it might be the only way forward.
Lots of steam doesn't work out of the box compared to Ubuntu.
But starting off with a new computer, copying over a config file from one of your existing files, building...and ending up with _exactly the same system_, including all those tweaks to _this_ file and _that_ config, and the cronjobs you've set up over time, and all your different rc files, is magical.
Also I've made android packages (albiet ones that don't use much Java) using the Nixpkgs repackaging of the Android SDK.
Make sure you're using Proton 5.0 until this [0] is fixed.
Most of the issues I ran into were just nix being different from other distros I use, so I did have to relearn a few things.
The remainder of the issues are the sorts of things one runs into with a non-rolling release distro. For example, a program I use got a feature I want last September. I'm going to have to wait until March for it to hit stable, since NixOS is on a September/March biannual release schedule.
The good news is that I am running the latest version of that package just fine now; Nix lets you install "overlays" of the package system into your home directory (or globally), and I just copied the package definition into the overlay, updated the URL and SHA256 sum to point to the new version and it "just worked."
Downside of course is when I upgrade to NixOS 21.03 (the march release), I'll have to remember to remove my overlay version of the package, or I'll be frozen on that version. There may be some fancy way to work around this which I haven't discovered, but since I have like 1 or 2 packages in that state at any time, I just manually do it when I upgrade.
Then anouther half day to get comfortable with home-manager to configure my user settings
If you're willing, its worth the effort