Reputable company. Probably with so many different versions, some aren't reliable, well designed or manufactured properly. Companies like Brompton and Tern to start; if they're too expensive Aventon and Rad seem reputable. If you like speed Ariel Rider. Unless you have an overwhelming desire to look cool or you're really going to ride in sand or snow, I'd avoid fat tires. They might ride a little better, but at the expense of weight (I realize it's not as big a consideration with a motor, JMO)..