IMO voice chat in discord is unreliable. The rest is great barring privacy concerns. I'd like to go back to mumble but my group's inertia is too strong.
Agree. I still use teamspeak as the primary voice chat with my main friend group. I use Discord for centralized access to different text channel groups.
I use both discord and mumble regularly, mumble is consistently better and it's run on a tiny vps that's doing other reasonably demanding cpu and network tasks at the same time.
Discord can go from great to terrible pretty quickly and the extra latency fluctuates a bit. ymmv.
They probably meant that while voice chat would normally be a reason to stop you from migrating from Discord, in this case it wasn't because the OP doesn't like Discord's voice chat. The rest is privacy concerns. I'm actually with the OP. IRC with Mumble is a pretty nice setup for casual conversations and it's really easy to self host (and takes very little resources). Filesharing is potentially a problem, but there are other services for that.