I have an EZEE rear hub motor that I set up on my mountain bike. I have about 1400 kms on it now. I have 2 big hills that I climb on my way to work. I pedal however the motor has a lot of torque. I could easily back off and allow the motor to pull me up. Because of the torque it has very good initial acceleration which is handy at lights if you want to beat the traffic. It has a very low hum to it. With the battery mounted on your rear carrier you can hardly tell the bicycle is powered.