I've been running NixOS for about a year now (servers+desktop+laptop) and I love it!
I config sometging once, push it to Git and all other devices follow.
Everything is in one place and everything uses NixOS/HomeManager modules, so everything is configured using the same syntax/language.
It is quite difficult to get started with, but it is so nice when you get the hang of it.
Also, I work in IT with declarative tools like Kubernetes and Terraform. NixOS lets me treat my machines the same way with declarative code, so it is actually pretty intuitive to me.
I am in no way an expert on the matter, but I will gladly try to answer any questions you may have :)
NixOS really is my endgame OS and after having tried many different distros, this is what I will be sticking with for the forseable future :)