A few things I don't particularly care for...
Battery-hog system apps have either had their names changed or been bundled in with some other stuff because I cannot for the life of me find AirWakeUp to disable it. It hogs my battery, and I don't use it.
When you DO force quit any app, it soon starts itself up all over again and boom, your battery begins draining AGAIN. Once you force quit an app to save your battery, you should be able to start it when YOU want to. For example, now there's apps for Samsung Gear. I don't use t, I don't plan to use it, I want to disable it. It won't let me. I force quit it, and have to go back in later on that day to force quit it yet AGAIN.
Because of all this, I've come to the conclusion that Marshmallow is a HUGE battery hog. I regret upgrading.