I'm using the wally world version... it works fine. Just make sure you keep the switch in the 4.5v location... if you bump it it moves. I put a drop of epoxy on mine. Also, my testing with 2 @ 3Ah 9.6v rc batts proved to be far less than fozzy's 7.2Ah 12v sla set up. The only difference between the two set ups other than the batts is the adaptors, so the wm version may waste some juice... not sure.
Matt