Having just upgraded to Ubuntu 8.10 my key observation is that it's important to read the release notes first.

http://www.ubuntu.com/getubuntu/releasenotes/810

There are a few bugs which have affected me

• there is no bluetooth support in KDE
• my wifi card only works in the US
  (there's a workaround and I'm back online)
•  Dual head display with xrandr is causing problems
  (my screen flashes and KDE is putting widgets in parts of the screen I can't see)
• Subversion has moved to version 1.5 and getting Eclipse to use a compatible svn library is proving tricky

On the plus side KDE 4.1 is looking very pretty, and the move to subversion 1.5 will be very useful in the long run.

I had hoped to get my 3G connection working as a previous update seems to have broken it - but so far still no joy.

update:
There's a solution for the Kubuntu Intrepid Dual Monitor Blinking
issue here: http://blog.nixternal.com/2008.10.22/kubuntu-intrepid-dual-monitor-blink...