It works. It works well BUT it floods ADs, some precede videos in sites - bombarded with useless, bogus ads - SHOVING them. As much as I like being able to easily present a browser change, the issue still remains.

CPU heavy, and when using isolated tabs, you have issues, it wont go BROWSER WIDE... you have to set per tab n stuff, its a PAI, and ive heard the dev has shut up shop and its full of bugs

Mozilla need to re-review this and give the golden cup to another user agent that can be trusted!

Aside from the white and black lists, this extension also has a list of domains where the UA should never be spoofed. It's never stated that it exists, and I found it out only when I accidentally opened the settings. This list includes domains I was using this extension for, which means that my UA wasn't actually spoofed there. 1/5, many thanks for a privacy leakage for no apparent reason.

it is difficult to master - you need a simple GUI option, where each site offers its own identifier, and not offer to write in a scripting language.
and of course the fox starts using the processor from 1.5% to 15%.

The modified browser profile does not pass Cloudflare's validation. https://webbrowsertools.com/ip address/

With extension enabled all the sites that use Cloudflare are don't load. Which makes this extension pretty much useless. I hope this issue get fixed then i will change my review.
Edit: Another review reminded me that it "makes the CPU go nuts every 30 seconds!"

This bugs websites that use Cloudflare DDoS protection in the default settings. Funny that their own official website uses Cloudflare protection, so there is probably a workaround but I prefer to just disable it.