Nix has more packages , by far. Nix also automatically handles the dependent libraries for each package, which is something you can’t do with brew on immutable systems. This means that Nix can install software like espanso, which wouldn’t work on uBlue derivatives otherwise.
I really wish the uBlue maintainers would have opted for Nix over brew for that reason. It’s not much more difficult to do nix profile install nixpkgs#package-name
over brew install package-name
. They could have even aliased it to make it easier.
Using containers on Linux has basically no performance loss compared to running on the host. They share a kernel and nothing needs to be virtualized (unlike containers on macOS and Windows), so anything you run in a container is basically the same performance as running it on the host.
I still agree though: using Nix is better than using Distrobox for many other reasons.