Overall, this is a really great chair. We love the extreme light weight. My petite wife has no trouble loadkng it in the van by herself. I like the many features like the easy folding, removable controller, charging port on the controller, phone charging port on the controller, and the remote controller. It even has a headlight, horn, and beeper for backing. So why the 4 rating and not a 5? No product is perfect and without constructive feedback, the company can't improve. The biggest downside are the instructions warning against frequent speed changes that may damage the controller or motors. This is a significant inconvenience. I try and keep the chair at the maximum speed setting. But the controller is sensitive and controlling the speed when making tight maneuvers or in situations with crowds of people such as stores or restaurants can be hazardous. Changing to a slower speed is essential. The knob on top of the controller comes off very easily. Everytime the chair is loaded in the van, care must be taken that the knob hasn't come off and lost. The batteries take 6 hours to fully charge from complete deletion. They can only be charged separately so that then becomes a 12-hour charging time for the two batteries with a necessary manual change from one to the other. The battery switch is more complicated than it needs to be. Move the switch to the left to use or charge the right battery. Move the switch to the right to use or charge the left battery. Why? This switching should be automated. Finally, when traveling on a plane, a protective cover is absolutely essential. So much so that it should come with the chair. Yet there is a backorder on the cover with no information on its availability.