I have been riding my E-Bike for 6 years, and love it.

The wife has been riding hers for 3 years and loves it too.

There are basically two different types now and three different ways the power is configured to be applied, thus some research is required to make sure you get the one that works the way you want to use it...

A hub motor, good for someone who want's some assist but still wants to put most of the pedaling effort into the ride, a mid-drive motor for someone who wants/needs more assist for bigger hills.

How the power is applied means a lot to me but most people don't seem to care.

Throttle; you can pedal or not.

Crank rotational sensor; you must pedal, but how much effort you actually apply into pedaling doesn't matter for controlling output of motor.

Pressure sensor in crank or hub; my preferred method, as power input is TOTALY controlled by how much pressure you put onto the pedals, 100% just like riding a real bicycle, depending on assist level chosen it's like riding with the wind on level roads or like someone pedaling with you up hills.

Power, to me anything more than a 350 watt motor makes it a moped, JMO... a throttle makes it a moped, JMO... and unless you actually need more motor or a throttle, it fails it's intended use as a bicycle... IMO