With asthma, the commuter was just what I needed to get up these hills in the DC area without having an attack. With the 20 miles range, that gets me though my day, I can almost get about 35 miles in, since I only use the assist for hills, and I call any incline a hill. It came in two days, was very easy to install. I did it myself. It took me over an hour because I was scared, and watch the video over and over. Before I install this, I never did any work on my bike, not even changed a flat. When I do group rides, people notice that I'm no longer the last person up the hills and tell me to slow down! They are impressed that I was able to installed it myself. I brought this in Feb. 2017, had one problem with the on/off switch which customer service addressed, sent me a new switch and instructed me on how to install it myself. They actually sent two switches, other than that, I had no problems with it. Great customer service that stands behind their product, great product, equals happy customer.
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.