I agree, I have had some bad experiences with RTH on a phantom 4, a few times things were going bad, dropping altitude and not following the course. So I rarely use it. HOWEVER.... I was flying an Inspire 2 in -35 celcius and my ipad quit due to the cold. As this happened, my spotter had just lost sight of it. My only option was RTH. I must say that day it saved my butt. Brought it back into visual contact where I could resume control and land without incident. I have now made a heating pad for the ipad to prevent it quitting on me again. And yes, I know it is not recommended to fly the Inspire 2 below -20 but the risk of failure is still outweighed by the cost of using a helicopter. So my advice is to use RTH only as a last ditch effort to save your Spark. Just make sure your RTH elevation is set at a safe height for your surroundings, and your home point is set to where you want it to return to (most important). A friend of mine told me about a trip he was on. They were on a car ferry. He saw a guy get a brand new mavik pro out of the box and start to set it up, a definite newbie. My friend warned him not to take of from a moving vessel. He said he would just take off and land. As soon as he took off, it appeared to runaway, but it was just the motion of the ferry leaving it behind, the pilot attempted to fly "back" but was not able due to his lack of experience, so he hit RTH and watched it disappear behind the ferry!!! I hope he had DJI care refresh to replace it!! The flight log would have shown pilot error, so he was probably not covered anyway.