Nix is better because you can use a lock file to fetch the exact revisions of each software. Even proprietary stuff is hashed so when you download it, it’s checked to be bit identical to the lock file hash before it’s installed
This means your setup on another machine is the same as long as the lock file is the same.
Also you can switch to an older revision, mix and match stable and unstable, keep your whole setup in a git repo. It’s basically everything you ever would want from a package manager (reproducible builds already done for the minimal version, soon coming to all 80,000 packages)