Well, of the three machines upgraded to Ubuntu 8.10 that I blogged about the other week, I've been mostly using the Sony Vaio notebook. Some issues have come to light (some good, some bad):
The new Network Manager (see the previous post for getting it to work) is brilliant, it's so easy to switch between wireless networks, and between wired, wireless and 3G networking. It's a joy after previous versions. So, definitely a huge improvement over 8.04.
Waking from suspend is much quicker for me in 8.10 than in 8.04. No idea why, I didn't change any settings!
The OpenOffice.org 3.0 I installed has difficulties saving presentations in PowerPoint format. I dare say that will be resolved in future releases, and it's not a showstopper for me.
The laptop point-blank refused to connect to a projector at a research group meeting. After that disaster, I tried using System | Preferences | Screen Resolution to see if I could get that working better. That seriously borked all my lovely Compiz desktop effects, and three days down the line I've not got them back. In actual fact, using xrandr on the command line is a better option. In the meantime, I'm seeking advice and help at the ubuntuforums.