They are very stable.
This one has a gps, compass, 3 linear and 3 rotational accelerometers. It carries a GoPro 3. If it loses radio contact it goes to 60' and returns to the takeoff spot.
Highly recommended (it's a blast!). ;-)
For real fun, google FPV.
Amazing technology!
Lot’s of science and physics behind that.
I dropped one in my Amazon Cart. I’ll do the research on it tomorrow, and either get/dump it.