Not user friendly, Terrible UI. User Can't simply SAVE custom user-agent strings. for standard use, FAQ (its really a "FA-Q") must be read.

Doesn't seem to be designed for easy mobile use

Popup is now completely gone...

1.Requires permission to access data on all websites.
2.The pop up doesn't resize properly.

custom mode not work

I had an addong called useragent switcher before and this aint it! Wish I could find it. I don't know what to do in this current version. I used the button on the tool menu and selected a newer version of Firefox but when I click test it still shows my actual version--52.5 ESR and it doesn't fool the addons site when I try to install a new addon. So far none of the user agent addons are working, so adding to the list of fails.

The menu occasionally shows "recommendations" (ads!) for other add-ons that are not directly linked to the mozilla add-on page. This feels shady, and generally unsafe.

I feel uncomfortable using this add-on and have uninstalled it.

This add-on can: Access your data for all websites

Really now? How about no. Why even such simple addon want ALL OUR DATA

askew

I really like the blacklist & white list features. however every time I press save, all my settings are lost

Opens a tab at the far right containing a webpage asking for money(donations), then shows google ads in there.

Completely useless.. I can't even save a list of crawler user agents (like Googlebot or Bingbot) with which I want to visit a site.. a single textfield isn't going to cut it.

They popped up an ad begging for a review when I was doing something, and then when I removed it I get a "why did you uninstall". I'd expect that in Chrome not FF.