Thanks kurisu - two quick follow-up questions:
First, do the rechargeable batteries that typically come with new Sony MD's (in this case Hi-MD) retain their charge, in the sense that I can rely on the 900's battery to consistently provide 8.5 hours in Hi-SP mode (per the Hi-MD comparison chart)?
Second, do the batteries last a long time or will I need to buy a new rechargeable battery every six months or a year?
Given your initial post I assume it is easy to buy new rechargeable batteries if/when they go bad.
Thanks again.