I just updated my home machine to 9.0. I haven't had much time to play with it, but I am quite impressed so far. Things certainly seem much faster (especially KDE).
However, I encountered a problem with the install. My previous install had a reiserfs root partition and I decided to switch it to ext3 as I was wiping it to do the upgrade anyway. However the partion tool apparently set the mount options for reiserfs rather than ext3 (fstab read: /dev/hda5 / notail ... which is a reiserfs option). This resulted in the boot sequence being unable to remount root as writable, at which point many things failed to work. It was fixable by using the rescue option on the install CD (wonderful thing that), but was annoying and would probably have stumped someone who hadn't seen it before.
