I recommend renting electric bikes from Cal Coast Adventures. The staff was friendly, the bike I rented was of good quality and it was in good working order.
I secured my rental of a Medium Specialized Turbo Vado SL online several weeks prior to my rental date which I recommend for a few reasons. This will ensure you receive the bike you want, the bike will be configured for you based on your online inputs before you arrive to pick it up, i.e., frame size, seat height, etc. It also makes the pick-up process quick and efficient enabling you to be on your way soon after arriving. Drop off was just as simple.