I'm in the Preview Alpha program and they just released XCloud Console Streaming for us to test. I gotta say, it's pretty awesome. Currently using my phone and a bluetooth Xbox Controller to basically control my home xbox over WiFi. I can play any Xbox One game (no backwards compatible games) and launch any app I want. The streaming quality is great (obviously dependent on your home network as well as whatever network you have your phone on). It works on wifi as well as mobile networks. I'd say it would be perfect to play single-player story driven games or racing games. Online shooters, not so much. It runs REALLY well, better than I thought it would, but there's still a slight input delay; enough to be noticeable and to put you at a major disadvantage.
I've tried the regular XCloud as well and it runs basically the same. There's only 4 games available to test for that, and I gave Halo 5 a try. Like the console streaming, it works great, but there's still a little bit of lag and my accuracy and k/d were way worse then usual.