Postive - The system is very efficient and powerful for the motor size

For the motor size (I purchased a 'legal' 200w motor) the system is very efficient and powerful. This is because  the motor is powering the front chain ring and therefore the power is not limited to the wheel speed (as is the case for wheel hub motors). This means you are using the gears like a car. You don't strain the motor up a steep hill because you can move to a low gear. And the motor can still assist you over 30kmh, say on the flat into the wind, by changing to a high gear.

This is the beauty of the design and why this should be a great system. Unfortunately the components used with the system and the pedal width required to get around the motor are major drawbacks of the compete kit. See the negative review comments for more detail.

The central location of the battery and motor is very good for the centre of gravity. It makes the bike's balance quite manageable despite the added weight, which is quite heavy compared to the bike weight. However, the battery connection components are poor and the motor location also has a major drawback. See the negative review comments for more detail.

Powering the front chain ring, with my assisted pedalling, I could get up to 40-50 kmh speeds on a flat road into the wind on a flat bar road bike. Normally I would be going 30 to 40kmh on my non powered bike.

Up a steep incline I could get up to 28-30kmh with pedalling, compared to about 18-20kmh pedalling without a motor.

Note that if you do not assist the motor with your own pedalling, you will hardly have enough power to get up that hill. But that is the point of pedal assisted power.

My commuting cycle time has actually improved on the harder leg (longer hills and consistent headwinds), trimming my normal time of approx 26 minutes to 21 minutes (12 km distance).