A bit of news update for the E5.
James of FiiO told me they have plan for inviting 5~10 head-fi'ers for an early review of E5, No specific detail yet but those who had reviewed the E3 on earlier time will be on their preference list. This will most likely happen after FiiO becomes a MOT in the forum.
Now about the E5: The release date is scheduled to be before Christmas, still no specific time yet. The demo set is currently being tested, and is claimed to have 'overall improved SQ, especially on soundstage and clarity. Original bass enhancement has been kept, but is optional to accommodate different headphone'