Choosing the right motor may be a matter of what suits your bike or what suits your riding style.

Hub motor – Explorer System
A hub motor system has good acceleration and hill climbing torque. It suits people that want an easy to use system with good range and smooth performance. You could think of it as the “automatic” system.
Easy twist and go use.
Keep original gears.
No additional chain wear.
Maintenance free.
Suits bikes with derailleur gears.
Suits bikes with disk brakes
Suits bikes with 26″ or 29″ wheels.

Mid drive motor – Summit System
A mid drive system has the advantage of driving through the bicycle gears. This allows for a greater torque and speed range. Great for people who want to ride as fast as possible or climb as steep as possible. Also it can fit to a wider range of bikes. Think of it as the “manual” system.
More technical ride, gear changing needed for best performance.
Additional wear on chain and sprockets.
Suits bikes with internal hub gears.
Suits all wheel sizes.
Motor weight is kept central in the frame.
Keep original wheels.
Greater top speed and climbing ability.