I've always used TouchWiz but wanted to use a launcher but they always lagged. I've been a TouchWiz user since the Galaxy S. I was always fine with TouchWiz. Oddly.. I don't like the new changes to TouchWiz in the last few phones.
I'm on Nova Prime now. I like it much better. I can choose icon packs, I can have more icons in the tray at the bottom of the screen. I have 14 because I have two pages of icons and I can scroll the tray from side to side.
You can also save your set up so if you get a new phone or have another phone, all phones are set up the same.
Also you can still use Samsung themes if you want. I use the themes just for menu colors etc. I use my icons and my wallpaper. There are extra widgets also with Nova. Your icons on the app drawer stay in alphabetical order.
I tried several over the years and like I said I always experienced lag, but Nova hasn't had any lag for me.