I still use macports, although it's mainly out of habit and I'll probably switch to brew on my next mac (I've also been trying out nix, and while I really like the idea, package availability and freshness hasn't been as good as macports or brew. Nix hasn't picked up go 1.7, for example).

My main concrete reason to prefer macports is that it has separate packages for every version of python so I can have them all installed at once for testing. I also like a lot of macports' technical decisions, like the fact that my regular user doesn't have write access to the installation directory. And macports has binary distributions now so the awful rebuild-the-world updates aren't as much of a problem anymore.