This comment isn't really related. I obviously love Discord and have been using pretty much since it became an option, but I wish there was a better UX for people who are in TONS of channels/servers. I find it hard to navigate all my current servers with just the icon -- especially when server owners are changing their avatars frequently.
I think their UX is awful, and their client is very slow in channels with thousands of users. They should open up their protocol so alternative clients can be created, or at least some IRC gateway.
I haven't made many calls but the sound was always crisp.
I agree on opening the protocol but if what you want is a gateway, it's already open enough for that.