Many people (including myself) have audio sync issues with the current builds of Kodi that include this feature. It goes in and out of sync all the time. It's almost there, but I'd recommend a bit more patience :)
I'm running Kodi 5.2 and in Settings > Video > Playback I have the option to adjust display refresh rate. Kodi itself runs @ 60hz but when I play a movie my TV switches to 24hz. Is that not the same?
This is a great build (I use the 29th of december build). Unfortunately, I think they are planning to implement these features in V17 of Kodi and not V16 that is in beta now. Also, I sometimes have audio sync issues with this build. Anyway, I'm very happy to see that the Shield is capable to do this. I hope the planned update to Android Marshmallow will make these features available in Plex as well (they seem to be standing still at the moment)
I have installed builds that support HD audio pass through and it won't do it. I set it to 2.0 and then enabled passthrough and it won't pass audio through correctly.
HD audio also works in the native app and archos, but Kodi obviously provides a beautiful UI for your blu-ray rip library.
Plex for Android TV officially has DTS-HD/Dolby True HD support as of a few updates ago, but at present is bugged, only using the DTS core audio.