This is the first UserAgent Switcher that I have tried which did as described! Good work!

It simply does what it is supposed to do. It would be nice if it was possible to change the user agent automatically at predefined time intervals.

Works as advertised :)

别用排名第一第二的useragent插件了
这个最牛B了
首先多，各平台各新旧版本
再来就是黑名单白名单自定义规则太强大

来使用百度简单搜索APP的useragent来访问百毒看看
Mozilla/5.0 (Linux; Android 7.0; wv) AppleWebKit/537.36 (KHTML, like Gecko) Version/4.0 Chrome/48.0.2564.116 Mobile Safari/537.36 T7/10.3 SearchCraft/2.6.2 (Baidu; P1 7.0)

すごく良い
非常に見やすいUIで、メジャーなOSはほとんど揃っていて、ブラウザも最新ブラウザでない限りある程度揃っている。
直接編集も可能
javascriptにもちゃんとカスタムUAが聞いている強力なUAスイッチャーです。

Minimal, under 1 MB (not like other extensions which can be up to 8 MB for no reason). Works as expected, great UI. Thank you for developing this, it's a far better option to the more popular extensions.

I love this add-on!
With the recent onset of Apple enforcing its "proprietary" right to use the emojis we are all used to, Slack, et al were forced to switch to their own, non-Apple Color Emoji typeface -- and if you're like me, they're HIDEOUS emojis. This extension allows me to permanently spoof the user agent to an iOS device for specific sites where I use emojis a lot. Like Slack, fb, etc.
When I was using Chrome browser, I could only achieve this by CTRL+I and de-toggling "Select automatically" under the Network Conditions sub-menu inside dev tools. So this permanent fix in Firefox is exactly what I wanted.

This app is so helpful.

Very good addon to go past google search filter limitations when using firefox android browser. I use it to whitelist google domains and load the chrome android user agent when doing google searches so i can have all filters.