It runs really smooth indeed..
Check for orphaned rpms though, as the upgrade isn't at all tidy.
I had rpms stuck at FC1 version because they were removed... like imap, the Fedora team has switched from the standard (I guess UW) imap daemon to Cyrus, but that didn't get updated (sounds logic, as it is quite a change).. If one isn't aware of that, he's stuck to old imap server which isn't being updated anymore...
I could imagine the same counts for a couple more packages...
Though... There are always some migration problems in the X environment... like shortcuts missing in the KDE start menu (yep I prefer KDE way above Gnome), and problems with altering Mime types...
But for regular use....... it's smooth
Cheers,