Just to make sure the record is straight, Mr. UberGeek is not my husband.
I don't know yet on the battery charger thing - I have not received it yet. I better get it before the 300k! I think the charger holds 2 or 3 batteries. The key (apparently) is to plug it into the charger before you turn the unit on and then leave it plugged into the charger. I don't yet know how long the charger will last w/o changing batteries in that.
I am also confused about the data storage thing because it says right there in the book that it stores up to 2 or 3 years of data. So I don't know when it would start overwriting. I will look on the Motion Based forum to see if people have discussed that. I don't think you could download to a USB key because you need it to interface wiht software like sync-ing a PDA.
The Edge does attach to separate mounts like, it sounds, the polar. So you can move the unit from bike to bike. There is a place where you can change the bike settings (tire size and weight of bike) as well.
I don't yet know how the directional settings work - how it tells you where to turn if you put a route in.