pkgsrc is a cross operating system package manager. It supports -- among many others -- NetBSD, Minix, SmartOS, Linux, and macOS. I like it because of this portability. It also has the additional, and I would say the best, benefit of being installed in the home directory and run completely without needing root access. I also like that I don't have to depend on binary packages built by someone else, say Joyent, although there's absolutely nothing wrong with it. Finally, it provides a large number of different packages. I have never encountered a package that I needed but was not available. In short pkgsrc is a portable, featureful, and flexible package manager. What's not to like?
pkgsrc can sometimes be a little behind native package managers, such as MacPorts on macOS, but it catches up quickly. For my use case -- getting access to multiple versions of Python -- it works well enough if I closely follow its trunk branch.
There's generally good and detailed documentation available for pkgsrc but an introductory guide that pulled in some essential starter information was lacking. This guide fills that void by making it easy to get started with pkgsrc and learn about some of its core concepts. Thus, I dubbed it the mini handbook or the missing starter handbook.