Ok, but could be better.

It would be great if it has a whitelist function or the exclusion list accepts regular expressions.

Enabling Fingerprint Protection prevents Firefox from opening windows maximized.

Don't know why there are so many negative reviews here. My PIA connection is neither 'broken' or unusable. My biggest gripe is the regularity of a proxy going offline while downloading, and I'll have to switch to another - irritating, but not a deal-breaker. And the reason it only gets 4-stars.

Best VPN

Works, but currently leaking DNS no matter what I do and also fails to check for latency of all servers.

I'm pretty happy with PIA but the addon doesn't work after Firefox 83 update. I don't want to roll back. Please fix the issues.
PIA doesn't connect to servers now. Latency is constantly refreshing.
PIA works in Brave though.
Please fix ASAP.

Update: The extension is now working properly with Firefox. I changed the star rating appropriately.
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I am a frequent and long-time user of PIA. It works well with native clients on all platforms and with the Chrome Extension. However, even with help from PIA Customer Support, I never got it running on Firefox. I tried many computers, many versions, fresh installed copies of everything, but it always hung during connect.

PIA works fine, just not yet on Firefox.

Still busted, get it together PIA

EDIT: mostly fixed, still a bit flaky on status in tooltip (doesn't match actual status, which you have to click on the icon to get)

Can Confirm Tambukey's Solution: Removing & Re-adding extension got it working with FireFox 71.0

To all who find the app stopped working, you have to fully remove it from Firefox then reinstall. I was able to get it to work. You will know it is working by either going to their main website or if your subscription renewal date is correct.