I got one of those in mint condition (in box) a while back too. It's a great little unit. It's stupid to argue batteries over it-there's virtually no reason to waste AA batteries if you're at home, so this unit comes really in handy then. I keep it plugged into the wall for long composing sessions. This way you save your AAs only for playing out.
Part of the reason I got the AC adapter in the first place. I have a deep seeded fear of losing save data due to my batteries dying in the middle of an LSDJ session.