Kool thanks for the link. Worth buying a couple spare batteries and be out for a while in the field.
A/C powered charger allows the Droid to pull the full 850ma it needs. USB is limited to 500ma so it'll always be slower. I doubt the split USB cable will charge it any faster, it's still only drawing the max 500ma the USB spec allows (both usb ports run off the same usb bus). Mine does seem to charge faster off the desktop PC vs. the laptop though.
OG Droid retired but serving as a wireless tablet now and then.