I think this article and the comments that followed paint an accurate description of Slackware.

Although more of my computers run Debian these days for various good reasons, the workstation I use the most still runs Slackware. I am often amazed when it takes me less time to get a new application running on Slackware than it does with other distributions where I have to fight wars with their package and configuration managers to coax them into installing and configuring software properly.

Patrick makes good judgement calls on the list of software he thinks he can include in Slackware to provide a reliable OS. Unfortunately this list seems to be shrinking with time. Maybe I'm just getting too used to the 20,000+ software packages available in Debian.

PS: Slackware is a good distro for people who (like myself) choose to drive automobiles with manual transmissions. Most of the reasons are the same.