Agreed.

What about ones that have a few extra?

Ctrl + r works as well :)

Not on Lynx (I just tried it and it seemed only to advance the text one step).

Fine: "any popular browser (and many less popular ones)." But I was going for brevity.

So I just did a bunch of experiments comparing Firefox Quantum to Vivaldi (Chromium). Firefox is in fact better except for its incredibly annoying rendering. I attached an image with a direct comparison. Notice the beautiful crisp text in V(Ch) vs the hideous, bloated text in FfQ.

Also, notice the GOG logo. In V(Ch) it is very sharp, but FfQ blurs the edges of the inner transparency for some reason.

If anyone knows know to fix that I will be very grateful, because other than this crap, which is annoying as a user (and also INCREDIBLY annoying as a developer) I am actually very happy with what FfQ brings to the table.

Personally, I find Fx Quantum to be significantly better than Chrome. Chrome has never been particularly good. the architecture has had a lot less thought put into it than Fx.

That being said, Fx has had some serious problems over the years and because the approach made in designing it is more thoughtful, it's taken a lot longer to get multi-process support.

If you haven't been using Fx for years, then the lack of support for some legacy addons is probably not something you'll notice. The interface itself is rather zippy and you have the ability to restrict cookies from being served to other domains, which means that when you're being rtracked by advertisers, they see one set of cookies per domain, so rather than 1 profile for you, they have one for each site you visit.

I'd personally, recommend giving it a try, the addons are still much better than what Chrome has available and it now is the second browser with U2F support, which should mean that sites will start allowing you to use Fx for 2 factor authentication via USB token.
You'd probably be better off with umatrix than NoScript. I used to use NoScript, but it's a serious pain in the ass because of the way it's designed. umatrix does a much better job of controlling what scripts run on a given site.

Ever since Firefox Quantum arrived I've been unable to view live streaming content on YouTube (I've been using Explorer for it instead whilst hoping that Mozilla would quickly resolve the problem).

On one of the channels I frequent the moderators recommend the following solution: So I've just tried it and it did the trick. However, I do wonder why Mozilla still haven't done anything about it themselves as lots of viewers seem to have this problem and the solution is rather simple. That is, if it really is a proper solution (feel free to enlighten me almighty computer nerds!).

All a quick Google search a week ago revealed was this thread and it basically left me none the wiser regarding whether or not I should enable VP9 (especially due to some of the conflicting information – see the attachment).

That would be why I was unable to watch the MST3K Turkey Day Marathon on YouTube. (I mean, it was on Twitch, too, but Twitch kinda sucks -- I was having problems with audiovisual desynchronization). It didn't even occur to me that Quantum could be the reason, especially with YouTube's super-helpful error messages.

That's too bad, but I take it you were able to watch it afterwards, right?

I haven't checked to see if the stream was archived on either platform, but I doubt it. (Well, someone on YouTube might've posted an unofficial recording of the livestream.) Honestly, it's the idea of watching it live on Thanksgiving that was the draw; most of the individual episodes I could probably find in various places, and the official MST3K YouTube channel probably has highlights of the host segments from between episodes.
"TL;DR" answer: No, but...meh.

I understand. Well, in that case it absolutely sucks møøse balls, no offence.