The coaster brake is a good design, just not very efficient. They have been in use forever. A well made one (and that excludes anything from Walmart) will not break, but it won't brake very well either. Before I gave up pedaling altogether, I rode a single speed (regeared a lot lower) cruiser bike with a coaster brake, but I never exceeded 5-6 mph. The coaster brake worked ok. Any faster and you will need some kind of front brake. Having it in the front is more important than what kind of brake it is. But I have seen cable operated brakes on cheap bikes turned into pretzels from hard use. They are made out of something you can almost bend with your hand. High quality V brakes will flip you right over the bars if you squeeze the lever too hard, but are also easy to modulate if they are adjusted properly, have decent pads, and the rim is straight, which it definitely should be on a motorized bike. From what I have read, some of the Chinese engines are better than others, just like some Chinese scooters are better than others, but none are great. I never got enough miles on mine for it to break, the POS tensioner got pulled into the rear wheel and destroyed the bike, and almost killed me. I was in the bike lane just a couple of feet away from 45 mph traffic. Fortunately I fell away from the traffic.
