Using my 340MB MicroDrive (in the PCMCIA slot adapter in the ePods) the ePod lasted about 3 hours and 50 minutes while playing Gladiator (2.5 hours, 170MB MPEG) before shutting down. The last 40% of power (according to the batt mon) went in about 15mins. It looked like it was going to go the whole 6 hours under stress, but no.
Not bad, about 4 hours under intensive processing and disk access.
BTW, I payed $190 shipped for my 340MB MicroDrive stuff (340MB Drive, PCMCIA adapter, cases for them, and a USB CF reader with USB cable). I got it on ebay in an auction by Cititronics.com, they have MicroDrive kit auctions all the time, but sell them for $249.99 on their site. I missed getting one for $174 by seconds before I got mine at $182 +8shipping. I was surprised it works in the PCMCIA slot in the ePods. And it is VERY fast transferring files to, 1 min., to get Gladiator onto it.