I'm looking at the performance stats streaming a game to my living room PC right now, and total latency is about 4-5ms, which would be unnoticeable even on a 120hz TV.

It does sound like some people do have pretty good results with it, but my experience is really not unique (I know personally many others who have similar).

With that in mind, I maintain that this stuff is very very far from perfect.

Yeah i've used moonlight/sunshine a handful of times and it's absolutely perfect, I couldn't even tell in most cases it was streamed.