Some of its advantages are, in a sense, unfair, because it doesn't manage my OS or its most vital pieces, which is part of why it's never, in nearly a decade, broken my system the way any others have. Homebrew's never made my system unbootable. Homebrew's never broken my GUI. Homebrew's never fucked up some driver that had been working totally fine.

In another sense, that's totally fair if you consider the platform as a whole. It's really hard for Linux overall to separate user packages from system packages, mostly because it's all mixed up together in a way that it's not on MacOS or Windows—but a distro could take that approach, if they wanted.

So, that'd be one thing. #1: Separation of a very complete and capable base GUI OS from the rest of my packages, with the base OS upgrading in lock-step and very reliably, and everything else totally disconnected from that.

#2 would be the package selection. The number of times I've found some lowish-star-count project on Github, blindly done "brew install [guess at package name]" and had it work, is crazy. Non-free stuff? It's there too. AFAIK Gentoo and Arch are the only ones that even come close—but then you're stuck either hoping rolling-everything doesn't break your system, or trying to maintain a jenga tower of pinned packages and still risking breaking your system when you eventually do update them. I'm actually not sure there's a single piece of software on any of my Mac hardware, for work or play, that's not either, 1) from Apple, or 2) installed via Homebrew. And I've never added any kind of 3rd-party repo to it.

(a minor point: it's also nice that I can guess the correct package name more often with Homebrew than on Debian and Ubuntu)

#3 is that it has never, ever broken for me, under normal operation. An "install" or "update" or "upgrade" or "remove" has never broken my package manager itself, or its package database, or left its installed dependency tree so deeply fucked that I lose an hour or five un-fucking it (in fact, I've never seen that happen at all with Homebrew). OS upgrades have occasionally made me run a one-time fix to its directory permissions. Maybe that's happened twice in a decade of use? AFAI can recall, that's it. Macports borked itself badly under normal operation every 3-4 months while I was using it, while having a smaller package selection and compiling (=taking way longer) more often—this was, IIRC, like 2011, though, so again, it may be better now. Every other package manager I've used for any serious length of time, I've repeatedly seen get in weird states that required substantial fiddling before I could use them for anything again, after what should have been boring and normal usage.

(see point #1 for why it would also be a lot more tolerable if it did have that trouble, than it is when that happens on, say, Linux, and indeed, that's the only reason I was able to struggle along with Macports for a little over a year before switching—I could just rm its directory and start over, after the second time from a script that did it for me, without causing any harm whatsoever to my OS itself)