It is working fine (Firefox for Mac): fast, lots of servers, specialized servers.
WebRTC Prevention included.
Sometimes got a connections error, this usually happens after a Firefox update. Solution: logout and login again or reinstall the add-on

Request:
A "Favorite Servers" menu like in the Desktop Application

PS:
Yes it is a paid service. You can buy a Lifetime Subscription here: http://bit.ly/2GkBzbu