I don't have the old one, but I have been doing some research on them as I am planning to buy one when we go in a couple of weeks.
From what I have learned from these forums, is that you can bring old Mickey Pal, and his transmitter thingy recharges (sorry about the poor technical jargon!) to have the new information when you arrive in the park.
I have learned that people are ordering the old ones on-line for $30 to bring on current trips rather than spending the $60 price for the new ones. I believe that the old ones have Mickey sporting his traditional red shorts, but the new one he is wearing a tux for the 50th Anniversary celebration.
Hope this helps some...