It doesn't work in simplest scenario. Like,

I type the url in the address box, say www.linkedin.com
Browser tries to establish connection and timouts.
I press add-on's button with "X" on it.
I see nice box with "Non-proxied page" on it and nice picture like My Computer -> about:newtab.
I see www.linkedin.com in the address box.
I stay puzzled about how the hell do I enable this add-on for this site.

I do not consider this scenario like anything near to "working". Do developers ever test their products these days?

ADDS. Adds everywere...

Couldn't enable on blocked site.

everything is working smoothly atm

Far worse than the version of older FF (before v57)

It doesn't work. Always I see "Non-proxied page". In Mozilla 56 - it works, So, now doesn't work.

The new version is terrible. I don't mind the premium but this is just plain downgrade.

Well like everyone has said, it slows you down unless you buy the premium version, well ok I tried it out and don't like that we have to pay for it so here is what really gets my ire up, it cannot be uninstalled, there are no instructions how to un- install it either. Isn't THAT an invasion of privacy and private property? This is MY computer and if i don't want a app or otherwise on my computer I will disable it or UN-install it. So do I uninstall Firefox and use another browser or do you guys share how to uninstall your app?