|This article comes complete with screenshots of the Slackware 9.1 Linux install. The are text mode screenshots, of course, and they look very similar to the first Slackware I installed in the summer of 1995.|
The reason it is easy for an experienced user is, first of all the init scripts and configuration files are easy to follow. They are generally well commented and it's easy to make changes using an ordinary text editor.
Not only that, you are getting the full, complete, standard releases of software in this distribution, installed in a sane manner. The way the developers intended. Therefore, when you go to install additional software not provided by the distribution vendor, you don't run into as many snags.
The packaging system in Slackware is quick, dirty and simple too. Slackware packages (.tgz files) are basically just tar.gz archives, that have install scripts that the packaging utilities execute.