it's all about the quality. toyota will put the time and money into making sure the businesses working on these installations will do it properly. the worry to consumers is electricians that have no clue about proper wiring on a high amp system.
Acutally the Toyota charger doesn't pull that high a curent, less than the typical dryer or electric range. If the level 1 charger can top up the car in 3 hours and the level 2 takes 1.5 hours that means the charger on the PIP will pull about 3.3 KW which, on a 220v circuit will be around 15 amps. The wall unit is capable of about twice that, actuall about 32amps I believe which is why it needs a 40amp circuit.