The Cyrusher doesn’t have the reliable Bosch motor that higher-end bikes sport and the Samsung battery is only good for around 500 recharges, which is less than you’d expect for a lithium battery. But with the low price point, there are bound to be some compromises. A great option if you want a decent, all-around model for easy trails or commuting.
As a counterbalance to the cute utilitarian bikes above, the Specialized Turbo Levo FSR Comp is a big, bad, and burly mountain bike. With 27.5-inch wheels, massive 2.8-inch tires, 150mm of travel in the front and 135mm of travel in the rear this bike is made to shred. The Specialized 1.3 Rx Trail-Tuned motor is designed specifically for off-road riding and features a double freehweel design that disengages the gear box at top speed to reduce friction while ripping downhill. The low center of gravity and stout parts make this one a relatively nimble handler that is ready for the rowdiest downhills.
Torque sensors and power controls were developed in the late 1990s. For example, Takada Yutky of Japan filed a patent in 1997 for such a device. In 1992 Vector Services Limited offered and sold an e-bike dubbed Zike. The bicycle included NiCd batteries that were built into a frame member and included an 850 g permanent-magnet motor. Despite the Zike, in 1992 hardly any commercial e-bikes were available.
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.
For those looking to hit the trails instead of the pavement, Yamaha has you covered with their new YDX-TORC electric-assist bicycle, which is powered by a souped-up version of their mid drive known as the Yamaha PW-X center drive motor system, which the company claims offers the extra power needed for more adventure and exploration on the trails, including a fifth power assist setting. As a more powerful e-bike, the YDX-TORC also demands a higher price of $3,499.
Because e-bikes are capable of greater speeds for longer periods of time than standard bikes, you want extra control. Wider tires provide traction and some bump absorption with little penalty. You also want strong brakes to slow you (and all that extra weight) easily. It's worth looking at the quality of the brakes and investing in bikes with better ones if you can.