The Nuvinci hub system is the best geared hub that I have ever used. There is literally no maintenance to be done on this drivetrain. I’d recommend buying it with the Gates Carbon belt because you’ll never run into issues like the chain falling off. You operate the Nuvinci system with a grip shifter and can of course shift even when you’re not moving.
Some power-on-demand only e-bikes can hardly be confused with, let alone categorised as, bicycles. For example, the Noped is a term used by the Ministry of Transportation of Ontario for e-bikes which do not have pedals or in which the pedals have been removed from their motorised bicycle. These are better categorised as electric mopeds or electric motorcycles.
Bulls electric bikes with Brose motors will always top the list for any long distance ride. Coming in with a huge 650 watt hour battery, Brose estimates that you can take these bikes over 100 miles on one charge easily. They also have 90 nm of torque, which will pop you right up hills even when you’ve got a full rack of gear in the front and the back.
After you decide which style of e-bike you want, consider the class. In the US, there are three classes defined by the type of assist and how fast the motor will propel you. Most electric bikes sold are class 1 or 3. Class 1 bikes have a motor (max 750w) that assists while you're pedaling, up to 20 mph. Class 3, also known as “speed pedelec” can also have up to a 750w motor, but it can assist you up to 28mph. Both of those are allowed in most states and cities without license. Class 2 have throttles that don't require you to pedal to get a boost. They're allowed on most streets, bike lanes, and paths, but less popular than the other classes and not covered much here (because we still love to pedal and the greater distances pedal assist bikes can cover).