Firefox has improved significantly. It's improvement strategy is mostly focused on what developers ask them to focus on. They've had great performance on the yearly interops
I'm surprised to hear that. I was under the assumption that it was generally acknowledged that the Firefox dev tools were far and away the best of the major browsers. I always find myself missing them when having to use Chrome devtools at least.
I feel like nowadays they both have basically the same featureset so maybe it's more about how well you know how to use them