At speed the E proved a stable and neutral ride, the motor engaged in good time and there was a reasonable amount of assist (the amount of motor assist is adjustable via a Bluetooth app up to 25kmph or 15.5mph). Charging of the in-hub battery is possible via a neat hollow charging bolt on the drive-side of the rear wheel. The Cooper E is one for retro-futurists and people who want others to say, "No way that’s an electric bike!"
E-bikes mostly use motors and battery options from a few major suppliers: Bosch, Yamaha, Shimano, and Brose. A few other brands exist, but are less reliable or powerful. Some, like the Yamaha system, have more torque and others are quieter. But generally all four make good options. Look for motor output (in watts) which will give you an idea of total power. But watt hours (Wh) is perhaps a better figure to use—it takes into account battery output and life to give a truer reflection of power.