Anyone played with Firefox's new VPN

Gidster

I read that Mozilla has added a VPN - currently free - to the latest beta release of Firefox (which is has just opened up to its user base for the first time in a while).
 Apparently it's only in the US. As I'm not a Firefox user, or in the US (although I could pretend to be with a VPN!), can anyone report on how good it is? I like the idea of a VPN integrated into a browser.
https://techcrunch.com/2019/09/10/mozilla-launches-a-vpn-brings-back-the-firefox-test-pilot-program/