As usual I get over-anxious and upgrade my main desktop (which I shouldn't as I rely on it for work and as a firewall), can't work due to bugs and end up re-installing the previous version.
Firstly Anaconda didn't recognize my pre-existing F10 install for an upgrade and just wanted to go head-long into a fresh install which I ended up doing. During this the custom partitioning screen didn't recognize my LVM partition, just showed it as type none, though going back and then forward again fixed the problem. After that Anaconda crashed twice on me, once after writing partition tables to disk (tried again and it was ok) and again at the end when it tried to eject my DVD. (though by this point the system was installed)
Once up and running things were better though still buggy and I quickly realize I'm doing something I shouldn't and get fed up. :) gwibber was busted (oh noes!), all my gnome-terminals crashed at one point when I hit some key combo, my ssh-agent died somewhere along the way, lots of seemingly unimportant kernel errors, and when I saw KVM looking broken (I now suspect I may have forgotten to install something) I quickly threw in the towel.
In the future, alpha/beta installs in guests. :) Must wait till preview/candidate releases for a system I depend on. You'd think that would be common sense...
Meanwhile now that I'm back on F10 I can do some testing on the Anaconda upgrade issue without actually going through with it, and probably spin up a guest and see if I can reproduce some of those bugs.