The battery life on my Handy Trax is pretty good. I've gone digging with it maybe four or five times in the past month and haven't changed the batteries yet. Those digs lasted three to four hours each.
Does the Handy Trax have other practical uses? I think so. Here's my video demo of it:
http://www.youtube.com/watch?v=LRPTtGIZpsII mix on CD decks primarily with one turntable; on the rare occasion I need two decks the Handy Trax fares surprisingly well. Dunno about the PT-01 . . .
The Handy Trax has a pitch control, which can be very nice while digging to see how a record might sound if you slow it down just a bit -- or speed it up. Oh, and it can play 78s -- though I've never had a reason to play one. It's nice to know I could do it if I had to though.
If you wanted to be a dick you could take your MPC 500 with you while digging alongside it (perhaps in a back pack or something) and stack up on samples for free

Even a MiniDisc would due I suppose.