Electric bikes are essentially low powered motorbikes. Their popularity arises from a quirk of legislation that means they don't need tax, registration or a license. In energy terms, it would be better to have a small internal combustion engine, as liquid or gas fuel is more energy dense than current battery technology.
 
If you think you need an electric bike, it is worth trying a good bike first. If your current slow bike is some supermarket dual suspension bicycle shaped object, then it's not you, it's the bike.
 
There are various electric bikes on the market. The cheap ones are awful. As this a specialist market that we know little of, we recommend that if you want one, go and talk to Ben at Kinetics.