After tuning the PID a bit, the Multiwii quadcopter flies better than the previous time https://www.youtube.com/watch?v=Sexb8Qa5Dk8
For simple circuit and line-of-sight flying, it is quite a fun machine. However, 450 quads with 3S battery simply has no punch.
Also, don't skim on your motors with cheap SunnySky angel series motors. They are absolutely rubbish. Putting 1045 props on these motors mean lots of vibrations.