We started using discord about a month ago. It was a blessing. Some engineers work remotely, while others work from HQs. We were using Google Hangouts, but GH lacks the ability to silence the remote user locally. If you silence a user, he must undo the silencing himself, which didn't fit well in our use case.
Engineers who were not working from HQs could not stand all the crazy sounds that came through office mics, so eventually they'd had to quit and be accessible only through slack.
The fact that discord allows us to press a specific key before talking, is amazing. It solved one of the hardest problems we had.