I really wanted to switch to Firefox, but after several weeks the thing that pushed me back was janky scrolling. It seems like a trivial thing, but it absolutely drove me first up the wall, and then back to Chrome.
It's significantly better (I would say on par with Chrome) if you set general.smoothScroll.msdPhysics to true in about:config. No one seems to talk about it but the difference is like night and day on my system. No clue why it's not on by default.
Also using Wayland (on Linux), gfx.webrender.all and a few other options can help quite a lot. For more details, I suggest you check out these two pages:
I've noticed that the default Firefox scroll speed is slower. As in the amount the page scrolls per rotation of the scroll wheel. This is a long shot, but do the settings here help in your case?
Yeah I try FF every 6 months to see if the scrolling has improved and each and every time I go back to using Chrome after a few days. I wouldn't say it's bad but it's noticeably worse than Chrome and I just can't get over it.
Which platform are you seeing janky scrolling? On desktop, you might try enabling WebRender (set about:config pref gfx.webrender.all = true).
On Android, you might try the Firefox Beta. It is the new "Fenix" browser that is a big perf improvement over the older Firefox Android ("Fennec") browser. All Fennec users will eventually be migrated to the new Firefox Fenix browser this year, but you can try Fenix in Beta now. Installed along Fennec as a separate app, it won't overwrite your Fennec user data.
Uncheck "Use smooth scrolling" in preferences to see if that makes a difference to your scrolling experience. FWIW, I have "Use autoscrolling" checked; most, if not all, websites scroll fine on my MacBook Pro and iMac. I cannot speak to the scrolling behavior on Windows.
Also using Wayland (on Linux), gfx.webrender.all and a few other options can help quite a lot. For more details, I suggest you check out these two pages:
https://wiki.archlinux.org/index.php/Firefox https://wiki.archlinux.org/index.php/Firefox/Tweaks
I applied most of the recommended (and some of the not recommended) tweaks documented there, and I'm very happy with the results.