Ouya isn't in most regional stores. I thought it was a buy online kind of deal only. Its still getting games and everything. Apparently developers quite like it for the indie and mobile games. I did note from a quick google that it was sent to retail stores but it was very lukewarm apparently in stores and to cut costs it seems its moved to an online platform.
Personally for £150 (£99 for the console and say £50 worth of games) its quite an attractive offer if you like that kind of stuff