The privacy access for this add-on is atrocious. Check under Permissions, and you will see:

-- Access your data for all websites
-- Download files and read and modify the browser’s download history
-- Access browser tabs

How is this OK? I understand their need to protect against phishing, etc, but access to ALL data, that's borderline unethical and vast potential for data leakage, and corporate maleficence.

Some additional quirks, as noted by others. Sites such as nextdoor.com will not allow login, even when PIA is not connected. The extension needs to be disabled.

One cannot connect if zscaler is running on the OS.

My router firewall was somehow blocking the extension from finding and connecting even though Firefox itself was working fine with router firewall active. I disabled router firewall and PIA extension connected fine. I then closed Firefox and activated router firewall. After that the Firefox and PIA worked perfectly except PIA won't allow changing location unless I repeat the process of disabling-enabling router firewall. If I use the PIA Windows application this issue is not present.
Edit: The issue also occurs with Google's Chrome browser.

So far, so good. I will update my review if I run into major issues. I think people experiencing issues in private browser windows do not have the option for it enabled on the extension. I am running the extension, and the desktop app at the same time. I have also tried it with the desktop PIA app turned off, and have found no difference.

Web Developer Google Marketing Global Partner

Very good vpn extension for Firefox. Occasionally I have long ping times, but overall I recommend PIA

On latest update, as soon as I open any private window it logs me off completely, I have to relogin to my paid pia user account to continue using it. Without private tabs it seems reliable enough, but any one single private tab - and it logs off. I've been paid user for more then a year now, but now I consider switching, since reliable vpn is required for my work.

Satisfaction Beyond Description...

Superb app. I love it!

UPDATE: The plugin has been completely unusable for several months now. The problem is that it constantly asks for your username and password, there is no way to save them, and entering them just results in another prompt.

It's working relatively well so far, but there are a couple problems:
1. We're forced to use Firefox's builtin tracking protection (privacy.trackingprotection.pbmode.enabled). I really dislike this, because I prefer to use PrivacyBadger to dynamically block trackers. This should be user-configurable.
2. I'm prompted to relogin every time I open a Private Window. I would much prefer for it to work seamlessly, remembering my credentials the way it normally does.