Have you used home-manager as well? Would be interested to hear your thoughts on the two, and what specifically makes nix-darwin so nice overall. I haven't used it before, just home-manager.

I've played with Home Manager, but I've never really used it long term as much as I have Nix-Darwin. (I'm not super interested in HM's dotfile management features, since I already have tools I like for that.)

What's nice about Nix-Darwin for me is mainly how NixOS-like it is. I like keeping its config under /etc and treating systems using it like NixOS. There are a few modules that I think are pretty impressive and atypical for the Nix world, like the Homebrew module. I'm not sure if HM has something comparable.

Homebrew is a big gap in home-manager. In fact, my current setup (and the most common I think) is to use homebrew for casks, home-manager for everything else (and I also do some Brewfile management with home-manager).

Yeah, that's what I like about the Homebrew module for Nix-Darwin: it lets you declare your cask usage in your Nix config.

I agree that brew's cask support is generally worth using even if the rest of brew is best avoided in favor of Nix or other package managers.