Personally, I don't use an "electric bike," and hope I never need to think about one. However, there are some posters here that don't understand the difference between the moped-style electric bikes where the manufacturer slapped on a pair of pedals (with immense "Q-factor") to get around government guidelines, and a true electric-assist kit, such as the Bion-X. I can speak with some authority on this, since, until recently, I worked at a shop that sold and serviced the same.

The Bion-X, though not without issues, is, in my opinion, the best of the bunch. It's still pretty heavy though, and if you have a mechanical, or run out of juice, you ain't pedaling that thing anywhere but on the flats, unless you're damn fit. And, if you are, why do you need an electric assist?

The only argument for motors, is for the truly infirm or unfit.

If you must have one though, find a shop that will support you. You'll need warantee help, believe me.