But I have a PS3 USB Mic. So will Discord USB mic work on my PC, even if I don't have me3 installed on PC? Umh. but that means I can't see anything. And the mouse also won't help. Right? Wait Wut?
Discord is independent of the game entirely. It's also cross platform, so you could run it on your phone or PC or tablet while playing on any other platform. It's also highly configurable, unlike many of the alternatives (I'm looking at you, TeamSpeak!) and it has no problem with you picking one of several connected mics, for example.
Siren
and I have been using it quite a lot in the Dark Zone, to avoid being overheard by all the Rogues lurking in DZ5/6. It works well.
Another tip, if you're on PC, is to set your sound devices to disallow apps from taking exclusive control. Then set your game chat to push-to-talk, so you can talk to your friend group on Discord, but can also make the pugs hear you when you want to curse them out for not doing objectives.