I'm a former Arch user who's been using NixOS as my daily-driver at home for about a year now, and I've really enjoyed it, even above Arch (which I'm also a big fan of).
The biggest gain over Arch for me is the safety net it gives you in making configuration changes. Once I've got the machine working, that state can be booted to for as long as I care to keep its pointer around. This means things like kernel upgrades are no longer the anxiety-inducing problem they used to be on Arch for me; if an upgrade fails, I can quickly reboot to the previous state without having to do anything special.
As a result of this, I no longer need to put off kernel upgrades when I'm trying to get something time-sensitive done! To be fair, I was running the ZFS-enabled Arch kernel, which was the cause of most of my problems. However, using the ZFS kernel on NixOS has been anything _but_ problematic; it just works, and keeps working!
Nix/NixOS also makes setting up a new machine just the way I like it a joy. If I move to another machine, need to build a new one, or need to re-image the current one for any reason, my configuration (stored in source control) follows me around without me having to remember all the one-off tweaks I did to make, say, hibernation work correctly.
I haven't yet mastered building packages since I don't find myself needing to compile things from source all that often, but I can certainly feel the pain of learning how to do so; it still feels like quite a mountain to climb before I'd really know what I was doing.
Learning to build your own packages is a bit of a chore, but once you get there, it could not be easier.
I suspect building your own packages for Debian or Redhat would be much more difficult.
Let alone getting that package accepted upstream, which is not that hard with Nixos.
The biggest gain over Arch for me is the safety net it gives you in making configuration changes. Once I've got the machine working, that state can be booted to for as long as I care to keep its pointer around. This means things like kernel upgrades are no longer the anxiety-inducing problem they used to be on Arch for me; if an upgrade fails, I can quickly reboot to the previous state without having to do anything special.
As a result of this, I no longer need to put off kernel upgrades when I'm trying to get something time-sensitive done! To be fair, I was running the ZFS-enabled Arch kernel, which was the cause of most of my problems. However, using the ZFS kernel on NixOS has been anything _but_ problematic; it just works, and keeps working!
Nix/NixOS also makes setting up a new machine just the way I like it a joy. If I move to another machine, need to build a new one, or need to re-image the current one for any reason, my configuration (stored in source control) follows me around without me having to remember all the one-off tweaks I did to make, say, hibernation work correctly.
I haven't yet mastered building packages since I don't find myself needing to compile things from source all that often, but I can certainly feel the pain of learning how to do so; it still feels like quite a mountain to climb before I'd really know what I was doing.