I use Firefox on my HTPC, running a 6700K with 24GB of RAM. Not new, but not “slow”. Clicking a YouTube video will cause a three second page load, even if the actual “page” says it’s finished loading. Videos will start to play audio before the page is rendered. Navigating back and forth causes issues like this too. Sometimes I can get it to show a video but not change the title or comments that it renders. If I accidentally click the “Shorts” hyperlink I basically have to close the tab to stop it from endlessly playing shorts in the background of the SPA.

It’s awful. The best example I experience on a day to day basis that the SPA as a concept is utterly flawed. YouTube is a fucking webpage that fails to work like a webpage and an app that behaves like a students rough alpha. An utterly painful experience, continually made worse by likely skilled devs who are managed by complete bozo losers. But at least the progress bar has an ugly pink hue now.

Docs just almost entirely does not function for me on Firefox on Linux. As in, I've had it crash the entire browser while just trying to type in a document. In general, Google just aggressively seems to be hostile to any non-Chrome browser using any of their sites. I'm sure they cloak it in "well Firefox just hasn't implemented this spec yet" but when it's functionally enforcing their browser monopoly I have to assume malice at this point.

Too many Google sites behave worse on any non-Chrome browser for it not to be intentional.

I wouldn't call them "obvious" reasons but I recently discovered that in Google Sheets under FF I couldn't duplicate a tab or copy a tab to a new sheet. I had to fire up Chrome to do that.

Oddly enough, Chrome had somehow lost my settings since the previous time I started it a few months earlier, as if it were a new install. :-?

I've not noticed any problems under YT Premium so far.

Depending on how beefy of a machine you're using, they're much slower in Firefox.