DE image can be written to eMMC if user so chooses (might imply losing existing Maemo OS)
User interface is MeeGo 1.2 Handset/MTF based, but some of the applications might be replaced with contributions from the community (eg. Peregrine, looking for more!) or new MeeGo UX.
There will be experimental MeeGo QML UX image as well available for N900, but only to show the current status and open the discussion for 1.3 targets.