I wouldn't call Nix 'blazing fast'; I wish Nix evaluation were 10x as fast as it is. But for many things it's much faster than Homebrew and has a lot of nice properties besides.
Pkgsrc is more conventional, and its package set is smaller. But the binary distribution of it from Joyent is is consistently quite fast, and the package quality in Pkgsrc is high. It's a fast, well-behaved package manager, and probably the closest thing to what you're looking for unless your main concern is macOS GUI applications.
It allows multiple versions, but only one can be linked. Never needed anything from homebrew in /usr/local, why do you need it? I don’t know if it leaves anything after uninstall, maybe config files in the home directory?
When I used to use brew, most of the time was brew doing housekeeping. You could see the title bar change processes twenty times a second, often ruby, as it did whatever it was doing, even for simple commands like search or before upgrade confirmation is approved.
I switched to devbox about a month ago after reading some comments on here about it, so far I couldn't be happier with it. It's certainly blazing fast, but also manages versions better, supports multiple users on the same machine, installs stuff to a sane location etc. https://www.jetify.com/devbox
+1, installation time of all kinds of software is much faster on nix for me. Over the years I've also been quite annoyed with homebrew for breaking all kinds of things, like the CLI interface or features like being able to easily install a pinned version of a brew
(used to be that you could just `brew install https://link/to/git/commit` which they disabled for "security reasons", the replacement is that you need to make your own tap which is quite a bit more effort)
Sorry if this is obvious, but when I do `brew install sassafras`, the bulk of the time between hitting enter and being able to run sassafras is downloading and installing. The overhead of Homebrew seems very minimal. Is the slowness coming from a side of Homebrew that maybe I don't see very often?
Pkgsrc is more conventional, and its package set is smaller. But the binary distribution of it from Joyent is is consistently quite fast, and the package quality in Pkgsrc is high. It's a fast, well-behaved package manager, and probably the closest thing to what you're looking for unless your main concern is macOS GUI applications.