Is there a [blazing fast] alternative to homebrew for macOS yet?

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.

For someone whose needs are generally met with homebrew, what are its major issues (aside from speed)?

99% of the time I spend running “brew” is downloading time, so I honestly don’t get this question. What kind of Internet connection do you have?

Brew is just fine as it is, unless you’re running an older version of macOS and it has to build packages from source.

I have been using pksrc on my macs for years. Also works on Apple Silicon.

https://pkgsrc.smartos.org/install-on-macos/

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

Macports might be worth considering

https://www.macports.org/

Nix

I see two people mentioning speed - is Homebrew doing something inefficient?

What’s wrong with home brew?