I own three trikes. Mooncool tk pro, 3Score, and Lectric. My favorite is the 3Score due to its 28 mph. It is stable as long as you ride it as intended. The mooncool is my next favorite, as it is the most stable. I dont care much for the Lectric, it is also to slow and not as stable as the other 2. The Mooncool would be my favorite it was not limited to 15mph. If you dont go beyond the limitations of what a trike is designed to do, no one should have any problems riding these types of trikes. Ive owned one for 2 years now and have never got into an accident or had any trouble riding them. Your mileage may differ.Mooncool trikes are "tricycle shaped objects". They don't look too bad, but they are abominably cheap and janky. I've whipped quite a few of them into good operating condition, which I expect they'll retain for at least fifteen minutes of riding. Less if they sit outside all the time like most trikes do.
To be fair, there isn't really a "nice" version of granny trike available. But some are nastier than others. Husky, Sun, and Worksman are crude but reputable. That's if you want to do your own conversion. Lectric makes an e-trike that I would consider a much better bet than Mooncool.