When comparing Slackware vs ArcoLinux, the Slant community recommends Slackware for most people. In the question“What is the best laptop OS?” Slackware is ranked 13th while ArcoLinux is ranked 27th. 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 Easy to install
Unbelievably fast for ArcoLinux with XFCE, Openbox, I3.
Pro Community support is great
Need to install Discord on cell phone and computer. Fastest way to receive help. Community is mostly European on Discord so getting help at midnight may be a challenge.
Pro Helps you to become a Arch Linux user
Pro Blazingly fast!
Startup time, shutdown time, everything in between.
Pro Easy to isntall desktop environments
Thanks to the manuals provided by the developers it is really easy to install more than 10 different desktop environments that'll work at the same time!
Pro Easy to install, handles system memory well, and a great way to learn Arch Linux
Incredibly fast, easy to install, tons of software pre-installed and easily installs more.
Pro XFCE, Openbox and I3
Finished Product with almost every tool a experienced user will use.
Pro Easy to install NVIDIA Drivers
Has option to install NVIDIA proprietary drivers. Runs great.
Pro Learning bash script
The fastest way to reload any Linux desktop is a script that will install all your favorite apps. Keep this file on a USB stick Update for any distro from Ubuntu, Fedora, or even Arch Linux back to your favorite apps in minutes.
Pro Efficient use of Memory, Easy to Install, Amazingly Fast
OpenBox on Arco Linux is AWESOME!
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 Small development team
Con Multiple types makes new user confused
Due to multiple types, new user might get confused and leave this all along.
Con A bit bloated
It is a bit bloated to many web browsers, text editors out the box. A simple customize menu's for all 3 desktops would have been nice.
Con No single ISO
Con Forums are not very friendly or helpful
