Slackware is for experienced Unix users who know what they want and how to do it. It is very friendly to those users. It has been to me for like 3 years. Except that's bullshit. Anyway, it could work that way with Ubuntu. First you just have to be able to use Linux, find things you like, things you don't like, get comfortable, read a bit about the internals, then you can get around to running Slackware. Just curious, what do you use Slackware for?