This alone makes me consider Firefox again!

Handoff (when it works)is just so useful.

Still a little flaky even for apple apps so interested to see how it works on Firefox.

I tried both Safari and Chrome of macOS but went back to Firefox for one simple reason. When watching streaming content if the browser was not in the foreground it would reduce the quality of the streamed content which could take almost ten seconds to revert back when focus was given.

Firefox doesn't seem to know/care if its not top window

Safari user, always play videos in a background window, never seen this. I suspect it’s not the browser’s video playback but perhaps more to do with how it handles spikes and drops in connection quality?

I didn't realize Handoff was even possible for third party apps!

I suppose there is no way to make it work with Firefox on Windows and iOS? That would be awesome!

The architecture for Handoff isn’t available on Windows (and it would be much more complex than a simple library since so much of the networking and Bluetooth stacks are entirely different between platforms), so no. I think Windows has its own, similar thing but, of course, iOS wouldn’t know how to communicate with it.