I try it every few months because I _really_ want it to work locally. Nix itself works pretty well, and most of the packages work well, but there's just enough brokenness in important utilities to keep me going back to brew for now.

It's certainly possible to mix them, and use nix for most things with brew as a crutch until nix packages get better, but I already have the App Store, stack, cargo, pip, gem, and npm trying to manage packages on my system, and I really don't want to add a brew replacement until it can be a complete replacement.