For everyone who thinks Hangouts works in Firefox, even Google admits it only works in Firefox ESR:
Edge requires a plugin to work, but it doesn't install correctly. (Basically the installer never finishes, and refreshing the page just redirects you to the plugin install page. It's possible I need to enable Flash, but that's never going to happen.)
Internet Explorer works out the box (maybe because I got it working before), but you have to enable SSL 3 these days otherwise it says it can't connect.
Downvote me all you want, but at the end of the day if you haven't tried it for yourself, you're full of shit. (Which given that this is the Internet, is entirely likely.)