I spent a bit more and bought a
crystalyte motor and controler because they seem to be the most durable, and fastest motors out there for the money, a friend and his wife have the same set up,
only on recombent tricycles .
I've also ridden the
Currie bikes with a hub motor, and they are nice only because they are simple, they don't have manual motor controles, it's all automated based off crank speed and torque, so basicly, the faster and harder you pedal, the more work the motor does, stop pedaling and you coast to a stop, the main draw back is that all of them I have seen have a 15mph top speed.