I think that if you need servo matching, built in regulators, RF filters, etc (the neat built in features of the Powerbox, made by Duralite also I think) then the Powerbox seems like the way to go. I have a Power Expander ready to install into one of my planes, have not turned it on yet but it seems like a great unit too. I don't think it has servo matching or built in regs, but it does have RF filters. (I am pretty sure it does) I think They both will isolate the receiver, keeping the voltage to the RX at around 5 volts and power to the servos at 6v. I am not an expert at them so someone with experience with both can chime in.
