While I lack sufficient experience using the "add-on" to give a quality review of it, I will say that as a subscriber/user of Proton VPN and the services, to which I've been paying for over the past year, have had one or two minor issues, which I have managed to resolve, but aside from that, I am satisfied, and happy with Proton VPN. (So far) I've tried 3 or 4 other (paid) popular VPN services, which I discontinued, after either having issues with their policies and/or after having researched them. Proton is my choice.