For an excellent and disruption-free experience I use Mumble and if I have to WebRTC, but the browser experience isn't as stable, performant and reliable. Nothing beats Mumble if video isn't a requirement. You can join free Mumble servers, host your own or rent a server. It's open source, so you're not at the whim of a company and integration with your operating system is much better. update 1: https://wiki.mumble.in…
I have poked around with Jitsi but its setup is too complicated for normal users.