I used Nova Launcher for about two weeks when I first got the phone 'cuz I had used it on my Note 4 and then my Note 5 for a little while, but they've made Touchwhiz so much better this past year and a half, that's all I use now! It's fast, smooth and doesn't chew up battery like it used to... hell, I think the later Lollipop version was the first to actually work well. So Marshmallow and Nougat versions are bullet proof, as far as I'm concerned! I'm sure you'll get a ton of other opinions but that's the way I feel... why mess with stock if it works great? I've changed Icons and wallpaper of course...