This page is my thoughts and experiances of using Slackware. I'll try not to duplicate links here and add most external links on the home page under Slackware
I've been using Slackware for several years now or the liberated version with all non-free software stripped out free-nix . Slackware is the oldest and probably the most Unix like of all the Gnu/Linux distros. It's conservative and pragmatic, easy to use and very solid. I'd say much more so than Debian which I used for 12 years until they switched to systemd.
Slackware is very community lead rather than corporate lead and a great way to see that in action is following the "current threads" on the linux-questions forum. Slackware current is the development version rather like "Debian sid". It seems more stable than "Sid". Possibly because Slackware has a smaller set of packages that make up the distro.
distrowatch slackware page