Yeah I keep hearing this but it never pans out, seems like in my experience a lot of people don’t know they might have to turn off an extension or two (ublock, built-in trackers, etc) to get a website to work.

I cannot open message in LinkedIn with Firefox linux. Haven't pinpoint the error cause though

I have no problem with anything on LinkedIn with Firefox/linux.

I have one internal corporate site which won’t work with Firefox for some reason, but never had any problems elsewhere.

Huh? I use YouTube all the time on Firefox and it's fine. Better than fine, really, thanks to the YouTube improvement extension I have loaded. Never heard of the other two though.

Google is essentially using A/B testing methods to slow it down for one group of FF users while keeping it absolutely fine for another. Funnily enough, I've been placed in this 'slowdown' group even though I am a Premium subscriber ever since it launched (post-Red renaming) and another channel on the same Google account has 0 issues in the same browser on the same PC etc.