I upgraded both my n810 and n800. It went OK so far except for the usually application installer horrors (taking minutes to do update, not finding things, etc), and that only Adblock Plus remains as an addin. It can't even be deleted, but manages to be undeletable.

My n810 has all kinds of junk. The n800 is nearly pristine. Both showed the same problem with add-ins/components/extensions.