I'm pretty sure ad experience will move some masses, I liked Chrome because Ublock works fine there, it has great extensions support and the best compatibility with the websites, but if you remove the adblocker support I would have moved (if I hadn't already) in a heartbeat
For a while I was a bit confused, because Mozilla said they would also implement V3 Manifest ...
by implementing Manifest V3 on its own terms, Mozilla saves developers who are switching to the new platform from having to support two different versions of their extensions (for Google Chrome and Firefox) at the same time. On the other hand, it allows content-blocking extensions that were originally built using the less restrictive Manifest V2 to continue working at full tilt.
Firefox is my daily, but the fact I have to fire up a chromium browser to use web serial or midi is an endless annoyance. Mozilla won’t add that functionality as they see it as a security risk.
Honestly, in my opinion it kind of is (though I'm not an expert on it). Except for convenience I don't think a browser should be allowed to access my USB devices. Though I would welcome it if it was enabled with the same kind of request that pops up when a browser wants to access the microphone or camera.
That is, quite literally, how it works in Chromium. Mozilla still sees it as a security risk, even with user permissions. Honestly, having to boot Chromium is a bigger security risk.