Similarly, some time ago I ran a team of 9 through Ventrilo (TeamSpeak alternative) after we struggled with Skype and IRC. It worked great, but we missed text for historical reasons; to supplement text we whipped up another IRC channel.

Discord really hit it off with gamers giving them the chat application they want (such as Steam, Battle.NET; formally Xfire) with the VOIP they used in conjunction. It's really an amazing product (who says Electron doesn't work?!) — I'm hoping they can stay around for a long time.