My Xbox One S was actually my first Xbox One experience on the Windows Anniversary update and it's been a bit problematic (if anyone's seen my previous posts in the thread) and I'm now starting to think either my power supply has problems or the update has problems I haven't heard anyone else really report.
All my previously noted network issues are gone -- my Xbox One S now successfully connects to XBL on pretty much every bootup and goes the same speeds as my previous 1TB Forza 6 edition Xbox. I eventually found out I was getting the weird Teredo IP address issue, so I followed the steps I saw online to fix it (basically just factory reset the console) and sure enough, it seems to have worked.
Now, I seem to get sporadic shut-downs, and instant on NEVER works -- it always boots to green Xbox One logo screen with the three circular load indicators, as if it's doing a fresh power cycle boot every single time. Sometimes the Xbox One just shuts off when I'm playing a game, sometimes it shuts off immediately after turn on (I'll just hear the console's "on" beep, then just a few seconds later it does the shutdown beep and sure enough, shuts down). It's happened at least 6 times in the past couple of weeks.
That said, I'm just waiting for a local GameStop to restock so I can go exchange the unit out. I don't know if it's the update causing stability issues or the power supply being borked, but I'm a bit frustrated with the current unit I have with the various network connectivity and odd problems with instant on and random shutdowns. My previous Forza Xbox One never had networking troubles or shutdown troubles... but this S has been nothing but problematic from the start. Hoping that (a) I discover that the latest update is having stability issues and I'm not alone with the random shutdowns and instant on never working or (b) the new unit is like-for-like stable with my old fat Forza unit.
Love the Xbox One S design a ton, and it doesn't seem like anyone else is really encountering problems right now... I also don't have a history with the Xbox One being unreliable like I did with the 360, so hoping it's just a bad draw with this Xbox One S unit -- really do not want to feel disappointed with Xbox again.