Hello there,
I think that the worst for the Ouya is his English-only UI...
I'm French and I'm a backer. When I received my unit, and booted it up, the first reaction of my family members was "But... it's in English, it sucks !".
The Launcher localization should be included in the next firmware update. Think to Transifex.com for making it.
Comments
I live in the Netherlands, but absolutely hate Dutch translations of programs (because they are often have weird choices of words, sometimes necessary to make the translated text fit into the available space, or just because the translator is a language purist). Many terms related to computers and software just are in English and don't have good translations.