Well, I have to say this has been the smoothest upgrade ever. Only a couple of applications didn't install.
I did the restore (I even tarred up /home/user and untarred it after the upgrade) and, just to start with a clean state for the browser, I deleted /home/user/.mozilla.
The sites that didn't zoom properly under chinook now seem to be zooming correctly.
I didn't try the new modest yet (last beta I tried choked on my big imap folders), but claws works fine.
I've not played with it for long but all in all it seems a solid update.
Congratulations to all people involved.