OpenSUSE and Slackware are catching up with the other distributions in prepping up their next release. openSUSE is now on the alpha 5 release of its version 10.3, while Slackware is starting with the release candidate 1 of its version 12.
You may get more details of new and improved features of each distribution from their respective websites at http://www.opensuse.org and http://www.slackware.com.
Personally, I prefer using Ubuntu but what the hey! To each his own, right? :)