For anyone and everyone having any issue with the Note5 Marshmallow update:
First things first after the OTA update, make sure to clean up your caches. That means app cache (through Menu>storage) as well as cache partition through the phone recovery menu. This will solve 99% of your odd issues.
Second, the best thing to do after a major OS update (not just security updates) is to factory reset your device. Do this twice in a row and I find it gets rid of all the issues you may see.
I've been running this update since it came out. My battery life is great, all my apps work fine, I see no ill effects. Be aware that due to the new permissions system in Android 6.0.1, you may have to enable quite a few permissions for your apps. So if you have an issue with a particular app, clear it's data through the Menu > Application Manager and double check it's permissions are enabled (for those things you want them to be enabled).
Also, Textra is the best SMS/MMS app available. Enable "use WiFi" and it'll work on WiFi calling. It's the only texting app besides the stock one that came on the phone, that will work through WiFi calling.
i still havent tried textra. been wanting to but keep forgetting to load it lol. been a handcent snob for quite a few years but its time to try something new.
Anyone is using the Power saving mode in Marshmallow?
I used it all the time in previous Android OS and it helped extending the battery life. In the Marshmallow, it stop the background data processes so you don't get update notification from emails and texts making the power saving mode useless.
google it. you can find tons of stuff like this that way. if he/she is meaning a partition wipe then each phones steps to do this is going to be slightly different.