Nice. Hope they release soon. My wife would not want me to join the beta program.
We've actually made sure that you can use the beta AND the stable release version at the same time for JUST this reason
When you download the beta, it actually shows up on your Apple TV as a separate application. So if you want to play with the new stuff and help use test it and give feedback and contribute to the app, you can do so while the stable version is always available working like it should.
Feel free to sign up for the beta here: http://goo.gl/forms/N9oWaqwd1y
Thanks!