Once everybody is using the same connectors, what will matter most for
electric car and plug - in hybrid owners will be how «smart» the chargers & cars will be; for example, you could set it to charge only certain times of the day or night, or to communicate with a smart
meter to only charge when electricity is at a certain rate, or only when there's a surplus of renewable energy on the grid, or to charge in a way that extends the life of your battery pack as much as possible,
etc..