Electric bicycles (of any type) are basically divided into two broad categories: those with the central motor and those with the motor in the hub (i.e. housed on the front or rear wheel).
The central motor is much more performing (and expensive), while the motor in the hub is used to set up bikes that make the low price their strong point.
ENGINE IN THE HUB
The motor in the hub, which mainly uses the pedaling sensor (speed sensor), has a generally lower thrust power than the central motor and the fluidity of the thrust is less natural: on the central motors it has now reached a level that the delivery is so fluid that it seems we are all doing it with our legs.
The hub motor, from this point of view, is more “raw” and the optimization less: this means that, in proportion, it is a motor that consumes more energy than the central motor (less autonomy).
For basic users who use the bike as a movement mainly on the flat, the motor in the hub is still a solution that allows you to save a lot of money and still reach the goal, that is to help us move. If you tackle technical and uphill routes, it is not recommended.
CENTRAL ENGINE
The central motor, normally (but not necessarily) combined with a force sensor system (torque sensor or torque sensor) is positioned on the bottom bracket (where our crankset / pedal axis is present). Suitable for the most advanced athletes and is the system used by all the major brands: Shimano, Yamaha, Brose, Bosch, Fazua, Shimano… when we hear these names we are talking about the central motor, not the hub.

It works by delivering a power proportional to the thrust that the user applies on the pedal: this leads to a smooth and not "jerky" pedaling, very satisfying in terms of cycling experience. This configuration is more suitable (if not required) for serious off-road use and uphill journeys.
The central motors with torque sensor are not particularly suitable for those who want to use their e-bike only to go to the office, or rather, the extra expense does not justify the performance.
PROJECTED IMPACT
Both are valid configurations, you just need to know how to choose the most suitable one for your use so as not to spend extra money and then not be able to take advantage of it at 100%.
