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pkgsrc is a framework for building third-party software on UNIX-like systems. It currently contains over 17000 packages.
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Pros
Pro Both binary packages and source build possible
Fast software installation is possible by using binary packages. It's also easy to build from source which allows for different compile-time options (like different UI backends) as well as gaining access to pre-release versions of software in certain cases.
Pro Offering tooling for backporting fixes
Backporting fixes can be done by cherry-picking updates from a newer branch (pkgsrc is released every 3 months) and creating a package. Sometimes bugs need to be fixed for production and there is neither a fix in newer pkgsrc nor the softwares upstream. So pkgsrc has tools like pkgdiff, mkpatches, etc. that help with developing patches and building binary packages from that. A bit of documentation about that process can be found here.