Boy, I am with you on this one. Full-time FF user too. The whole CSS grid thing is very well done and useful.
Well, I don't really work with CSS much, but js.
Are you consider the debugging tools well done as well? And do you know chrome dev tools? With its elaborate performance tools etc?
I currently work more with CSS so I find the debugging tools on both good enough for my purposes. I do know the chrome dev tools and find them to be good, just happen to prefer the FF dev editions ease with layout.
Yeah but it's somewhat laggy compared to chrome's.
To write and debug code?
I mostly use Console, Network and Inspector tabs and I rarely debug (in general.)
Especially Network tab in Firefox's dev tools is much superior to Chrome's one, IMHO.