The only weakness I could see was that it seems a little heavy and under powered at take off. Once it gets going, it flies fine but it lacks in acceleration, take off roll was long and even then initial flight and climb was a little wobbly. Reading the manual it states that "After initial flights the 10x5E propeller can be replaced with a 10x7E for more power". I will certainly do that even before my next flight, it is easier to have the power and not need it than to need it and not have it.