First of all, the VPN works fine. You need to make an account, and you only get 10GB for free, but I can get over that since it's still a pretty good deal.

BUT. This extension messes with you configs without ever warning you about it or giving you the choice to disable it. It will automatically disable all prefetching and Firefox network prediction, even if the VPN is toggled off and you disable all privacy options in the extension settings. I believe that an extension that tramples over my preferences without even mentioning it ANYWHERE or giving me the option to disable this behavior is not worth it if you truly want to be able to have control over your own browser.
Obviously this doesn't affect you if you have prefetching disabled anyway, but I do believe that any form of unintended behavior is pretty bad.