Firefox still has some UX deficiencies on macOS, I do use it on Windows though.
What really turned me off is how long it took them to implement video autoplay blocking. I sent them about four dozen requests, reports and outright pleas, and they didn't even add it to the roadmap until after I had given up hope. They were about two to three years late on that one.
Chromium's dev tools are still ahead by a mile as well, the Performance inspector has saved me days worth of debugging time.