http://indefinitelywild.gizmodo.com/what-s-wrong-with-electric-bicycles-1702986234

Some fairly sensible comments from the designer. Especially this.

Electric bicycles tend to either be too cheap or too expensive. The affordable ones are total pieces of shit that, even before you get to their terrible motors and crappy batteries, are just bad bicycles to start with. The expensive ones are great, but cost way too much money. Once you get to carbon fiber frames and full suspensions and Dura Ace components, you’re already talking a stratospheric price and the electric drive just takes that even further.