Apple has released a software update (4.2.2) for the latest generation Apple TV. It involves bug fixes and performance improvements.
For example, it resolves issues where audio and video are occasionally missing when playing back certain content. Also, a new audio output setting allows you to switch to 16-bit audio, for increased compatibility with some TVs and AV receivers.
You can install the update on your Apple TV by going to to Settings -> General -> Update Software and following the directions there.