My user.js file is entirely platform independent. I use it on Linux, Windows and even used it on my work provided Macbook. FYI: user.js only contains the settings you want to change, it’s not the whole prefs.js file. It’s just 63 lines.

I agree that chrome feels cleaner and needs a lot less fiddling to get right, but chrome is effectively dead for me. I switched to firefox for much more important reasons than a few UI annoyances.