To paraphrase one of the best 'Star Trek: The Next Generation' episodes, 'Best of Both Worlds,' both Arch Linux and Slackware represent the best of all the OS worlds: the power of traditional Unix, the elegance of BSD and the ease of mind of Mac OS X. This is an article outlining the differences between--what I believe--are the two best Linux distros around today. Mind you though, 'best' doesn't always mean 'easy.'
"Both distros feature text-based installation that are quite equivalent in terms of features and ease of use. However, I will give Slackware a slight preference here because of all the networking/package installation that's done by the installer, while Arch requires the user to use a text editor to edit the /etc/rc.conf to its liking, as this requires some extra knowledge..."