The only thing about this radio system and electronics is that the throttle isnt proportional. Or, at least on my buddies apex it is not. Youll pull the trigger 20% of its throw and get nothing, 21% will give you 100% throttle. It is impossible to 'crawl' with it. You have to use short 'jabs' at the throttle to get it to move at a slow pace.
While I'm not sure if there is a defect in his unit, I would just be weary.