Wow, I would have never expected NVIDIA to come out with something like this, but it sounds very well done. They definitely made it powerful enough to run any game.... but that doesn't mean much if it's only Android games.
It's a bit too weird for me to accept. They put the console hardware in the controller, which scared me that it might be one hell of a heavy controller, and it might overheat in your hands. Streaming a game running off a PC is only logical if you'd rather lay down and play away from your desk in your house, but it's still better to just hook up a game controller in your PC and play on a larger screen.
Ouya is already outdated and worthless compared to how revolutionary this is. Having a portable console/controller/display all in one is a very cool idea, it would feel like real console gaming anywhere you are on-the-go.
As for the GameStick, since it lacks a screen, it's not something you're going to ever pull out of your pocket and play on-the-go. Millions of people have Android devices that they can pull out and play whenever they want, which is way more practical than this.