For my group this wasn't about mic settings but mumble being bad out of the box. Maybe because we didn't pay for the servers and used a free something, maybe because of bad luck, I don't know, but every experience we had with mumble was terrible. For teamspeak, while the voice part is great, the message part is (or was at least in ~2016) lacking compared to discord. We were coming from skype/twitter which had better support for """rich messages""".