Slackware was also my first Linux distro. I have always liked it for its beautiful simplicity and getting out of your way.
When I first saw a SuSE install I felt pretty overwhelmed and overloaded by all those ridiculous choices, checkboxes and dialogues. Plus the multitude of wizards and tools for making tasks "easier" were just an abomination and very often did not work.
And I always hated RedHat's automatic update tool which would read update information from a central server but search for the RPMs on a different mirror then - because very often those mirrors were not in sync.