The Verge reviews the Google Nexus Q →
Google has a lot of improvements to do. The Q falls short on many aspects. There is no TV interface, you can only control the Q with Android devices. Audio quality seems good, but video playback seems laggy. The Q lacks many features compared with the Apple TV. At $199 compared to $299 for the Q, the Apple TV would be my pick.
My biggest disappointment concerns the collaborative playlisting. Unfortunately, it has not been thought through:
While tapping on the options for a given song allows you to add it to the current song queue, selecting that same song directly will immediately begin playback, bypassing what's already in the queue. Even worse, if you're viewing a list of tunes in playlist, album, or artist sort, selecting one song will add it plus all subsequent songs to the queue. Testing the feature out with a friend quickly pivoted from a fun musical collaboration into a frustrating game of accidental playlist-jacking. To be fair, this implementation problem could be resolved with a software update — but this is the marquee feature of the Q. It's so important that the device's name is a cute play on "queue." If there's one feature the Nexus Q should nail from the end user's perspective, it's this one — and it falls short.