All clans' voice chats that I've been in were via Mumble, hosted on the server of whoever was the Linux nerd of the clan (nowadays that's me). No complaints about that software, but I heard lots about Skype and Teamspeak indeed. Mumble also uses TLS for encryption and authentication so it was more secure than anything else at the time as well, and more secure than Discord because the admin could maybe listen in but that's another team member and not a stranger working for a commercial entity

I hate the Discord UI/UX as well (e.g.: sluggish add hell; need to press a few specific pixels on mobile to show the mute button and other controls that automatically fade out if you don't touch them for 2 seconds) but apparently what they do well is filtering out super loud eating noises, or that's what a friend said when I asked them to mute when they were eating crisps with the mic pointed directly at it as well as blowing on the mic with every breath. Apparently they never got complaints doing that on Discord

I feel like an old person when muttering something about mute button etiquette to myself while writing this comment. If machine learning can fix that (if it doesn't require proprietary datasets from storing millions of peoples' conversations), I should let it ^^'