Thanks to clever engineering, the Electric Brompton folds up identically to the non-powered variety. It is heavier than a standard Brompton of course, but quite light by e-bike standards. It has small , suitcase-style additional wheels that come into play once folded up, and the way the weight is balanced means it is quite straightforward to trundle along in that state.  

All three road bikes receive their power from Yamaha’s PWSeries SE motor that comes with four levels of support: ECO+, ECO, STANDARD, and HIGH. The mid-drive motor supplies a maximum of 70 Nm (52 ft-lbs) of torque and cadence support up to 110 rpm. The motors are designed to provide assistance up to 20 mph (32 km/h). Any faster, and it’s all you providing the power.

Gearing: none (many hub motors, one motor revolution = one wheel revolution), fixed gear reduction for more torque, varies when geared motor drives the chain through the bicycle gears which increases torque about 50% (in low gear) for better hill-climbing and offers better top-end speed (in high gear) than direct drive systems using motors of similar wattage.

The other thing to consider is that this is a Kickstarter project, so you aren’t directly purchasing from the company, but rather “backing the project” in exchange for a bike. Technically, Stark Drive, or any Kickstarter creator, could cut and run with the money, leaving their backers without legal recourse. In this case though, Stark Drive has already run a successful crowdfunding campaign for their previous bike and demonstrated their ability to deliver, so this is probably at least somewhat safer than a brand new Kickstarter start-up.
You turn it on by pressing the green button on the battery once for low power and twice for high, although to be honest, there is not a lot of difference between them. After that, you just pedal. There are no gears, no chain to muck up your trousers (a motorbike-style carbon fibre belt is used instead) and not that much difference in feeling compared to riding a normal bike.

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).