The difference is that in Ouya it can allow you to use the touch screen part of the controller to play any game that doesn’t support the gamepad functionality which basically allows you to play a ton of stuff on the android market.
Also, the Ouya is an open free development platform, they encourage the community to root it, mod it and expand what it can do. They won’t even void your warranty if you root it and experiment, this open concept is something that will greatly expand it’s adoption in my opinion which could lead to advanced concepts, experimental game types and even mods that may change the way we interface with our gaming consoles.
The fact that they tout every single game for Ouya will be free to play in some way, meaning you can free trial or demo every game, or each game is free with just ability to purchase micro-transactions and upgrades mean that most users will pay about 1/3 the cost of a gaming console, but pay many hundreds less for games and be able to try dozens if not hundreds of games before buying the select few they think are worth spending the money on.
Many are touting that Ouya will crush the competition from Steambox and Project Shield by Nvidia. Some even say the traditional console model will diminish as a result of Ouya, big developers are starting to line up on board and I am excited about Final Fantasy 3 releasing for Ouya which may be a reason for me to pick it up the day it comes out.
You can now pre-order the Ouya on Amazon.com by the way so you can make sure you have it the moment it releases to the public in June 2013. But the Kickstarter backers will have it first several months earlier the lucky blokes.