Clickbait? Its not "VPN providers" its "VPN provider software", I never even thought of using their software, most just give you the credentials for OpenVPN/IPSEC/PPTP or similar. Also if anonymity is of "real" concern you should never use a system that knows your real IP address in the first place. Instead create the vpn tunnel on a separate host system and run something like Tails in a VM (or better yet separate ph…
OpenVPN leaks DNS on every default Ubuntu installation I have tried. But I think it's actually Ubuntu NetworkManager's fault.
The WebRTC leaks discussed in this article are not prevented by OpenVPN either (last time I checked, which was a while ago). You have to disable WebRTC in the browser.