Just to add to the pile of anecdotal evidence - same here...I switched to Chrome some years ago when the speed difference was just too much to ignore and switch

Just to add to the pile of anecdotal evidence - same here...I switched to Chrome some years ago when the speed difference was just too much to ignore and switched back to FF a couple of months ago after I started realizing the growing firmness of the cold grip Google has on the web more and more...There's absolutely no noticeable speed difference any more, fans on the laptop are as always and it's been smooth sailing since (on Mojave). The only thing that still annoys me when developing is the lack of websocket frame inspection - but as a "regular" user, no issues at all.