[Philips, Sony, TCL Android TV] skorpioskorpio:
OK, after a couple days of screwing around with this update, here's some insights:

The "Featured Apps" section, on mine anyway, is now beyond annoying and is outright broken, so really going into "Settings > Apps > Running Apps" finding "Sony Select" and "Sony Shelf" and "Force Stop", "Clear Data" and Setting "Notifications" to "Off" is kind of a requirement, like I said for me anyway. This removes the section entirely, and downloaded and installed user apps will show up in the sortable editable apps section. One caveat seems to be, and I am not sure if this is because Sony Select and Sony Shelf are disabled or if it's yet another bug in Marshmallow, only apps installed from the resident Play Store app seem to show up. In prior versions, and again without those Sony apps disabled, you could push apps by going to the Google Play website from a PC or Tablet, select your Bravia from your devices list, if the app supported it, install it and it would just pop up on the list after a few minutes. Now it doesn't do that, they're installed but you have to launch the apps from either the "Settings > Apps > Downloaded Apps" or use HAL or something like it, create a menu entry to get to them. Very contrived. The advantage to "pushing" an app is that if you have a paid for app, usually you can push it to all your devices and not double pay for the Full or Pro version if you use it on, say your phone, tablet and TV. The local Google Play App is not aware of your purchases elsewhere even if it is aware of your GMail ID.

Also enabled Developer Functions by continuously selecting "Build", there are some selections now for limiting background processes. Though not sure they do much.

I use Android Task Manager Pro on my phones and tablets and saw that it was "supported on all my devices" and allows you to, pretty quickly, see what the ill behaved processes are, and set Auto-Kill for them. Seems to work on the Android TV. While watching Amazon Prime, video studdering seemed to proceeded "Not Responding" messages from FoxNow and FXNow apps, though while installed, do not seem to come up in the Task Manager list so I am not sure why they'd be running while Amazon is running but not before. The app that was particularly buggy for me was HBO Go which seems much more behaved now.

Oh, also one of the things added by the Marshmallow update was this Samba Services Manager thing, which is supposed to give you sidebar info on shows you are watching, though I did not see anywhere where it was actually accessible. I assume this only works with tuned channels, which I have none, and honestly who does? I kind of view internal tuners in TVs anymore as kind of a relic from the past that could pretty easily be served by a USB dongle accessory for the handful of people that do either OTA or the even fewer people that have non-DRM cable service. Anyway, in Task Manager, Samba tops the list on consumed memory, and can't see that it offers any benefit, and frankly I'm pretty suspicious of any company that would name their product for essentially a Linux box: "Samba", when it has nothing to do with "SaMBa" the Linux implementation of SMB/CIFS network file sharing. To me this is sort of like naming a streaming protocol "Extended Media And Information Licensing: (EMAIL)" it's just dumb and naive. Anyway, Disabled, Force Stop, Clear Data, Notifications: Off, and set a Auto-Kill in Task Manager in case it tries to start anyway.

So far Bluetooth seems to behave with 3 devices, a keyboard, mouse and touch remote, add an Android phone running the Android TV remote app and the touch remote seems to drop out and become unresponsive, so no Android Phone control for me, I guess.

I also stopped and de-notified "Game Shop" as I personally have no real need for embedded games, nor do I have a Playstation controller connected. I personally do not see this as an important feature in a SmartTV that has a half a dozen inputs into it. I mean if you want that get a gaming console and plug it in, anyway just MHO.

Now things seem to be a lot more stable, the interface a lot cleaner and I am not in some desperate quest to ditch the whole Leanback Launcher interface, or try and hack at the underlying Linux and freeze myself in time from future fixes. Still terribly disappointed in the Marshmallow update, but it's now worlds better, of course while doing all this my phone auto updated to Nougat, WTF.