When comparing MacPorts vs pkgsrc, the Slant community recommends MacPorts for most people. In the question“What are the best power user tools for macOS?” MacPorts is ranked 41st while pkgsrc is ranked 62nd. The most important reason people chose MacPorts is:
MacPorts eschews Apple-supplied libraries and links sources against its own making sure that the experience is the same regardless of what OS X version is used.
Specs
Ranked in these QuestionsQuestion Ranking
Pros
Pro Provides a consistent experience across OS X versions
MacPorts eschews Apple-supplied libraries and links sources against its own making sure that the experience is the same regardless of what OS X version is used.
Pro Easy to use
Detailed instructions on the homepage are easy to follow. Official GUI app is also available
Pro Generally very up to date
MacPorts generally gets new software soon after it's available. This way users will not have to worry if their software is up to date.
Pro Nice variants system
MacPorts has a variants system that allows customizing builds with author provided options.
Pro Has many more packages than its competitors
As of this writing, 20K packages. 3 to 5x more than other current package managers.
Pro Requires SUDO to install apps
No need to worry if some rogue app will change your binaries or configuration.
Pro Download libraries instead of relying on Apple's caprices
Considering just how often Apple breaks things, any reduplication of of Apple-supplied libraries with the canonical sources is an asset.
Pro Fast
Written in Tcl & C, it's generally significantly faster than the competition. Tcl is also quite readable and comparable to Ruby, so it's also friendly to newcomers.
Pro Supports older Mac operating systems
Homebrew dropped support for old Macs. MacPorts still supports them.
Pro MacPorts is a native application: C + TCL
No need to install Ruby, or any other programming language.
Pro More packages than competition
Pro Apple Silicon Ready
With Apple moving over to its own silicon, macports has been ready for the move to ARM since 2.6.4
Pro Initially started and developed by Apple employees and supported by Apple itself
Reading the story behind MacPorts, it is the only one that was developed by Apple by an Apple employee. In fact it is the same person that was responsible for creating the FreeBSD port system.
Pro Great support for older systems
Pro Most of the available packages work
For example, trying to install Finch using Pkgsrc doesn't work, while installing it using MacPorts works perfectly. Finch isn't even on Homebrew's radar.
Pro pkgin is an apt-like tools for installing binaries from pkgsrc
pkgin aims to be a tool similar to apt/yum for managing pkgsrc binaries by relying on pkg_summary for installing, removing and upgrading packages and dependencies, using a remote repo.
Pro Adapted for use on over a dozen different operating systems
Has been adopted to be used on several Unix-like operating systems and Windows. It's also the default package manager of DragonflyBSD and of the (now discounted) Bluewall Linux distro.
Pro Installs and works in the same way as MacPorts
Installs its own dependencies which means that it is very secure. Cannot install anything unless you use the "sudo" command which is in keeping with the Unix philosophy.
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.
Pro Does not need Xcode command line tools or Xcode.
This means that you can install it fresh on a new installation of MacOS and have all your favorite apps installed right from the start.
Pro Works easily with Ansible
Can be used from within Ansible to install packages on macOS.
Pro Easy installation if you use 3rd party scripts
This one works brilliantly.
Cons
Con New Packages and Updates take time
Macports isn't the first choice for developers producing new packages or binaries for macOS. Nor is it the fastest in getting updates. But in general, it usually is one of the most up to date and will be updated eventually. Some would see this as a con in comparison to Homebrew.
Con Bad at limiting dependencies
MacPorts has a habit of pulling very specific versions of dependencies for each package. It downloads different version of already existing dependencies even in cases where the existing dependency version would have worked seamlessly.
Con Downloads unneeded libraries duplicating functionality already provided by Apple's libraries
As MacPorts eschews Apple-supplied libraries and links sources against its own a large duplication of functionality across MacPorts and Apple libraries can be found.

Con Requires root permissions (sudo) for installation of packages
A really good security feature, but some see it as a con.
Con Relatively complicated setup and installation
Installing and setting pkgsrc up is a bit more complicated than in other package managers where it often consists in running a single script.
Con Not so broadly used on MacOS as compared with MacPorts
You do not hear about Pkgsrc as openly as you hear the words "HomeBrew" or "MacPorts".
Con Outdated packages
Some packages are outdated.
Con Can't install some packages
Even building well known packages (except MacPorts) from source using the ports can fail.
