Платный, и замечен в утечках DNS.

Good because allows multiple profiles and patterns. But bad because too large UI, so can't see even bit longer profile names, neither on icon nor in options except when editing profile. Also changing username only does not work, keeps using old username...

Not working with Firefox, unless you use desctop mode. Ok if you have uptodate smartphone. When you have limited data and only use.home WiFi then usefully.

Still not working with firefox 83.0 update...

no proxy auth popup with latest versions, worked with previous versions or if user/pass correct in pattern definition

It was quite ok for the purpose I used it for, although not so comfortable to configure with its user interface, but now getting worse.
I am still using it as I don't want to look for an alternative due to time issues, but probably not so long anymore.

It really got worse with the version 5.

I rolled back to version 4.6.5 manually and deactivated the auto-update for this addon.
I lost all my settings due to the auto-update to version 5, which they also mention in the desciption of the new version - below - with saying sorry, but a sorry does not help.
The import function should work and should exactly solve the supposed "Firefox limitations" but it doesn't do..

Although the old design wasn't really good either, the new design is just a nightmare.
Besides that the new version displays my proxy password in cleartext on the screen - no way!