My biggest issue with it is that my content, the content I already OWN, is hidden away under the "My Computer" section. I don't understand how this is not a bigger issue.
I get they want to hype their iTunes sales but leave it as an "iTunes" button and make the content we already own the focus point of the UI. That is the part of the new UI that absolutely infuriates me. I use the Apple TV because I want an easy, relatively cheap way to wirelessly stream my content on my network to the TV and have a device that is 100% compatible with all the other Apple products. If I see a "Movies" icon on the main screen that icon sure as hell better take me to a listing of MY Movies that I already own. I'm not going to repurchase a film or entire television series that I already own and have ripped at a higher quality to my networked storage.
If this is Apple's new direction then I'm bailing for Linux and getting a Zotac Zbox or any number of other units whose focus is on MY CONTENT.
I can tolerate them wanting to shill their iTunes crap to an extent. When they start slamming it in your face with an endless array of icons and essentially disguise any content you haven't purchased directly from them then it is too aggressive and borderline hostile.
Then there's the idiotic tile array, practically invisible outline denoting what you've selected, undeletable icons for useless crap that many people in many markets don't even care about or can't use (NHL, NBA, Netflix, etc)
They let the marketing team give input to the software department and that's where it went all tits up.