Motor: We have a blog post showing some motor differences: https://www.ebikekit.com/blogs/news/its-whats-inside-your-motor-that-counts Cabling is probably the #1 issue when something goes wrong. Good connectors, good cables, and good assembly (bike shop!) are crucial Strain reliefs on all cable joints! Where you have a junction box or a connector, the stress is concentrated over a small area near this stiff spot on the cable. This can cause small breaks on the internal...
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.
Cost: Good e-bikes are not cheap, and unlike most bikes, the costs associated with owning an e-bike don’t end when you hand over your credit card in exchange for a shiny new steed. The average cost of operating an electric bike is around $390 a year, including maintenance and charging. You’re also likely to need to change the batteries every 3-5 years so factor that into your costs.
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).