RTH is a good feature, but needs to be understood. Since I never fly out of LOS, I only see it saving my AC if something were to happen to my RC. In that circumstance, it would be a true lifeline. Imagine your RC somehow ceasing to function. How would / could you recover your bird without RTH? Simply put, you could not.
Those that have crashes 'because' of RTH do not understand it and have not set the RTH altitude high enough to clear obstacles, or fly out of LOS and count on it for a blind return.
I was flying one evening and a guy ran up to my bird as I was landing it shouting, "There you are, I thought for a minute I lost you". He was holding a RC and then realized that I was landing an inspire and not the P3 that he was missing. He had flown around a tall building and when the signal was blocked by the building, his P3 entered RTH and rose to his preset altitude. What killed it was it hit an overhead power line and immediately crashed, destroying his quad. He never saw it happen and found the wreckage later. Had he remained within LOS, it would not have entered RTH and crashed.
All pilots should check their RTH altitude often and should initiate RTH a few times to get familiar with the way the AC behaves when engaged in it.
