Obviously, GFN can have a latency edge on Xcloud just because you can run at a higher FPS. That's why I say, for best results MS probably should have gone with 3 consoles. Even if the 3rd wasn't available to consumers and was just for Xcloud. Create a box that can run the same visual settings as the X model at twice the FPS and use it in the cloud. Would really reduce the latency of the streaming experience and make it more comparable to the console experience.
But, with that said, Xcloud works great for me as it is in most instances.