For those that have said they'll use it for more of a media hub, that's fine. But as a gaming system I think it will fail.
As a gamer, this is what I see as a huge flaw in this system. It's cheap. It's $99. It will heavily revolve around the existing app market where the typical game is $0.99-$2.99. Sure, developers have said they'll make games specifically for it, but that will result in a higher price for a higher quality game. Look at this forum, people went crazy and cried that $15 was too much for Final Fantasy 3. I'm positive that "cheap" mind set will continue into the OUYA's life cycle where people cry if a game costs more than $3, but the same people will turn around and cry that they aren't getting quality titles.