Yeah but I really didn't like Hangouts either, although I'll give it a try again. One of my biggest complaints was that it didn't display a preview of a new incoming SMS on the lock screen like Samsung's stock SMS app does. Unless there's a setting option I'm not seeing.
I've been using textra for quite some time and it is great. Very light so it doesn't take up much room and it customizable enough for me. Give it a shot.