This might just be from my own limited experience, but firefox developer tools provides way too much information when inspecting elements on a page. It gets to the point that its distracting. I don't need to know where an element is positioned on the page, I can see it on the page itself. There might be perhaps settings to change this, but the native settings are not to my liking. I also have noticed on the on/off many occassions I have used it in the last 2 years, there is sometimes noticable lag delays when inspecting items. I find the interface much less intuitive as well.

I will argue that firefox does have significantly better support for CSS grid layouts (as it came out with support first), but I don't use that often, and recently chrome unleased these tools in the last year to my knowledge.

I use chrome inspection tools tab for the following purposes now mostly: elements, console, sources, and network. I don't use any of the other tools very often, partially because I don't need too. This is what I mostly compared firefox developer edition tools too.

I've found when I wrote my first stylish extension and just debugging in javascript chrome is just a much more pleasant experience. I have never really run into any problems asides some issues regarding its native RWD tools for handling body margins. Firefox did not have this issue, but this is why I use the linked tool in the above comment

I was aware when I wrote that post that its not called tampermonkey scripting and it was called something else but I didn't remember at the time. Now I know its userscripts :)