I don't have the EP version of the Superstar, but I do have the 40 sized ARF. It is extremely stable, when set-up following the instructions, and trimmed out by an accomplished instructor. Do you have any help on learning to fly it? Flight times for the EP should be between 8 and 15 mins, assuming that once you have taken off and gained altitude that you back off the throttle. My 40 sized will fly a long time on 1/3 throttle.