I was driving through Ocracoke Island, in the beautiful OBX two weeks ago. I saw a cool kids trailer at the ferry station.

A woman brought it on island for her 4 year old. She rented a bike and rode with him all week. They enjoyed everything. She told me it worked perfectly, and she found it to be an excellent step up from a strider, until her son grows a bit more. I am not familiar with these but I'm glad to hear people like them.