I personally prefer Discord. The functionality and simplicity of permissions trump Teamspeak in my opinion. For the argument of poor sound quality, there is an option in Discord to turn up the tick rate for the channels; maybe that could solve the "poor voice" quality?
I have a server within my house that I run my Teamspeak server on. I've signed up for the Teamspeak 5 Beta, so I will hopefully be on the first to test out the new program. There hasn't been much information released on TS5, but I'm hoping it will bridge the good qualities of both Discord and Teamspeak 3.