I tried briefly Ubuntu 6.06 or 6.10, can't remember precisely which. I found the software
upgrade system to be superior to the one of Red Hat/Fedora and the hardware support better.
However, one thing I found unbearable about Ubuntu was GNOME. It is very un-configurable
compared to KDE; for starters, there is no way (or I could not find a way, even with google)
to change the size of the panel, something trivial in KDE's panel. The file manager of Gnome
lacks important features, e.g. terminal window or the ability to split windows
horizontally/vertically. So I removed the Nautilus thing and installed Konqueror (plus all
the supporting software). Then I lost the desktop - it turned out the desktop surface is
somehow depended on Nautilus.
Being fed up with Gnome I tried Kubuntu. ALmost immediately I found the Network Manager was
buggy and that was the end of any Ubuntu on my laptop.