I would like to know as well before buying controllers!
I have the 850C and I've used it a few times and it works great. I bought a controller for Xmas because I wanted to get more into gaming and because I had the PSNow built in there so I figured why not? I had a friend come over who is ore familiar with gaming and he couldn't believe all the games available. He also told me they are the full fledged games, just like with the console.
Buy the controller on Amazon and try it for a month and return it if you don't like it. I think you have to get the dulashock 4 though to be wireless.
I used it on my ps4, which I assume is the same service (PSNow) and it worked great with 20mbps down
I have it on my X850C, but can't bring myself to use it when I also have a PS4 and PS3 right next to the TV. The only Sony app I want for my TV now is PS Vue, but for some reason Sony only has this app for iOS right now. They aren't even supporting their own devices running Android yet.