(This is probably subjective, and I don't consider myself and expert.)
I think Firefox feels best on Gnome-based Linux desktops: Fedora, Ubuntu, etc.
Windows 10 is also a fine target for Firefox; I never encounter any problems there. I hear some features are missing on touchscreen laptops: gestures, etc. I could be wrong.
Firefox has always had a little bit of funkiness on the Mac. Little UI things, battery killing performance issues, and so on. YMMV. But I still used Firefox on the Mac as my default for many years, and it was fine.
I think Firefox feels best on Gnome-based Linux desktops: Fedora, Ubuntu, etc.
Windows 10 is also a fine target for Firefox; I never encounter any problems there. I hear some features are missing on touchscreen laptops: gestures, etc. I could be wrong.
Firefox has always had a little bit of funkiness on the Mac. Little UI things, battery killing performance issues, and so on. YMMV. But I still used Firefox on the Mac as my default for many years, and it was fine.