I haven't had the problem at all since the newest beta firmware was released. I should note that I currently have significantly fewer analog devices attached than I did before, but I've played about 20 hours on my gamecube recently and haven't had an audio dropout, and haven't had the digital inputs do it since I updated as well (the digital inputs get far more usage).

I'll note that occasionally when I turn the 1070 on using my Harmony remote, it will immediately turn itself back off, but I figure that to be some error in the remote programming and nothing to do with the 1070, but I thought I'd mention it just in case.