I’ve been thinking about going down the battery route with the QC. The main reason is to be able to use it when playing in places with no power supply, but as someone who has trouble with electrical interference even at home (crappy old electrics, the house need re-wiring!) as I understand it one major advantage of a battery pack is that you eliminate the electrical noise.
Apparently this is even true if you plug the battery charger in to the mains while using the QC, as the Krisdonia units allow pass-through charging, so you are actually powering from the battery while the battery is charging…