Just for general info, there's a lot more to a reliable system than the FC though. I make a living with military grade UAV's and all the components, systems, and software work together to make a good system. With our FC's if GPS fails, which is a separate system from the FC, any hope of RTH goes out the window, pre programmed or not. Even Pixhawk goes into a self leveling altitude mode because it no longer knows where home or a launch point is.
Never, ever try to use RTH during a GPS loss. The FC, any FC, no longer knows where it is and can go anywhere because it does not know where to go.