I ran into three problems. One was a known bug while generating locales, which I got out of by simply aborting that process. One was getting the nvidia binary driver working -- again, I had this set up in Gutsy, why can't those settings be taken over to Hardy? Why did I have to re-enable it all again (while working on a resolution of 640x480, no less)?
The other one was the usual VMWare kernel module compilation which I always have to do when a new kernel is installed. But this time, something in the include files borked up the compilation script, so I had to apply a few manual patches to make it all work again. It is working now again, though -- there is a significant advantage in not being the first one to switch over, as there is a lot of stuff to be found about issues and their solutions through Google a few months later...
I enabled the desktop effects, they're fun. I really need to read up on how to get Compiz doing it's magic, and what the keyboard shortcuts are.
Also, I am really getting tired of people who claim that Linux does not "just work" while Windows does. I have had to install drivers for my motherboard on every Windows install that I ever did. I fail to see how that is any different than enabling a binary driver in Ubuntu -- in fact, it's easier in Ubuntu.
Sure, if one is CLI-phobic and doesn't want to cut-and-paste some instructions into a terminal window, one does best to stay away from Linux. But it's not like Linux is some kind of black hole that will suck all the productivity out of you, as xkcd seems to claim.
If Windows suits your needs and you want to stick to it -- that's fine with me, really. But Linux suits my needs better.