If you have the tools to remove the crankshaft and axle, installation of BBSXX system and clone system is very simple. But nothing is easier to install than a front wheel hub motor, where you just remove the original wheel and replace it with an electric wheel. We generally don't emphasize this too much because the time spent installing any conversion kit is far less than the time you save from riding, and you should install the system that suits you. If you are concerned about installation and moving the auxiliary device to different bicycles, it is difficult to place the front wheel hub motor on top to reduce trouble.
Due to independent propulsion, the electric wheel hub motor drive leaves any number of sensor technologies available to measure rider pedal input, including chain tension, rear release, rear axle bending, and many bottom support torque sensors. For mid-drive, the motor is coupled through the drive chain, so these sensors can differentiate between pedal power and motor power, so you will be more troubled by what comes with the mid-drive system, and so far its functionality is very limited. Some have torque sensing, but most have only a basic pedal frequency sensor.
In order to make the mid drive motor work properly, the rider needs to shift gears through gears when accelerating and decelerating, and also exit the motor power at each gear shift to avoid severe gear shift transitions. This constant backing and re-applying between each gear shift can increase the motor power burden and cause some speed loss, while using wheel hub motor, you can continue to get uninterrupted power throughout all gear shifts. A displacement sensor product allows these motors to cut off automatically, but if you stop in a mid-drive system and forget to lower the gear first, you will be powerless. The motor will start with low acceleration and inefficient high gear. For people who ride bicycles regularly, this may not be a problem, but for those who don't have this background, the simplicity of not having to shift gears all the time is a big attraction of electric bicycles. Riders can often keep the bike in high gear and use the wheel hub motor to accelerate quickly, so there is no need to shift gears up or down every time they stop and go.