NixOS user here. My experience is that if you track unstable, you will have bleeding edge packages within a day or two from an upstream release. Likewise, due to how Nix works, you can pick and mix from stable, unstable, and your own custom expressions to your heart’s content. My personal preference is stable, with a very small subset of packages from unstable that I try to peg back to stable once there is a new stable release.

I will not pretend that there is not a learning curve though, Nix is a bit of a beast.