I actually don't switch to Firefox because I'm on i3. I fell in love with surf-like browsing, and am able to somewhat get the same result with chrome in --app mode. There is however no way (to my knowledge) to get tab-less full-window browsing in Firefox.
edit: I just installed the tab-less extension, edited my userChrome.css, and I'm really happy with the results. I'm going to give Firefox a go from now on!
I don't have a screenshot right now, but it's just as you might expect, the whole tab line is removed (the nav bar line with menus comes to the top instead). [This post](https://www.reddit.com/r/firefox/comments/736cji/how_to_hide...) talks about doing the same thing in the context of tree-style tabs. Good luck!
