When comparing Slackware vs PrimeOS, the Slant community recommends Slackware for most people. In the question“What are the best Linux distros that don't use systemd?” Slackware is ranked 2nd while PrimeOS is ranked 33rd. The most important reason people chose Slackware is:
Uses stable, plain-vanilla packages from upstream.
Specs
Ranked in these QuestionsQuestion Ranking
Pros

Pro Stable
Uses stable, plain-vanilla packages from upstream.
Pro Strong adherence to UNIX Principals
Pro Ideal to learn more of Linux
Follows the original Linux roots. It still sees Linux as a free clone of UNIX so the distribution tries to be UNIX-like.

Pro Package management
Uses standard tar archives with shell scripting as packages.
Pro One more distro which is init based
Some users don't like to install systemd based distros because they increase booting and processing speed.
Pro Oldest surviving Linux distro
Besides Debian (which was first released in August 1993), it is the oldest still maintained Linux Distribution and was first released in July 1993.
Pro Super fast
Pro No systemd
Pro Dual boot at single click with PrimeOS installer
Pro Standalone OS, better performance than any emulator
PrimeOS is standalone OS thus provides 2x performance than any emulator as emulator runs on a host OS.
Pro 3x better performance than windows budget laptop
Pro Android Gaming on PC
PrimeOS is equipped with a key mapping tool, DecaPro whihc let you play any Android game at the comfort of keyboard and mouse.
Pro Android Ecosystem with Desktop Interface
PrimeOS provides access to the whole Android ecosystem with complete desktop interface. Now use multiple apps on single screen with minimise, maximise and close option.
Cons
Con Not user-friendly
It is made to be KISS (keep it simple, stupid), so you have to do everything by hand.
Con Large size live ISO
One needs to vain 3GB+ data for downloading one slackware ISO.
Con Narrow repos
Doesn't offer the same amount of options as other distros do.
Con Niche/small community
Slackware is its own niche and has a small community.
Con Very slow release cycle
Hasn't updated in 3+ years.
Con Dependency issues
When it comes to dependencies, Slackware shows more issues than many other distros.
Con Windows software aren't compatible
