During the test flights in order to find a good pid configuration I had some crashes (pilot error :p ). In total 3 motor arms broke and the outside prop protection broke at 6 places. But the fix is easy. Just glue evertying togheter with 5min epoxy and the quad is ready to go. But no motor and no electronics were damaged.
I think I'll stay with the current pid settings as used in the testflight in the video. So the next stage will be the integration of altitude hold or bluetooth control depending on what will be deliverd first.