I do the warranty work for Baja in my area. The Doodlebug are pretty well built. The only problem I've had with them is in the prep at the point of sale.
When you get it tell the salesman that you want to ride it around the parking lot before you accept it. Pay attention to the throttle and brakes. When you get it home, LocTite every nut and bolt. Keep the bushing on the clutch lubed per the manual.
It'll be trouble free for the most part.