Discord really is a high quality service. I remember a friend of mine in either late 2015 or early 2016 told us to give it a shot instead of Skype. This is the same friend that tried to get us to use Mumble and Teamspeak in the past, but we were dissatisfied with the audio quality. We gave it a shot and never went back.

Now, however, I've been very interested in open source alternatives. Not to make them take over, but as a backup option to have around. I think Matrix with Jitsi Bridge for video and audio is the current leading self-hosted alternative, but nothing beats the convenience of Discord.

If there comes a time where Discord gets hit with some anti-privacy/serious censorship issues, then I'll really dive into the alternatives, but for now, they really do a great job (not to mention their medium blog is very interesting).