It stopped working properly on Firefox versions of months ago.
Some websites have no issues at all.
Some have the issue only in one iframe but not in the other.
On some websites the scroll is sloppy.
On some websites there is no movement at all.

As soon as I disable the addon every website is scrollable again.

It was good for some years.
It's not anymore.

This averages to 3/5

しばらく前から、スクロールする量が不安定になっています。設定値の倍ほどの距離をスクロールしてしまう状態になることがあります。
下方向がおかしい場合はページの下端まで、上方向がおかしい場合はページの上端までスクロールすると（そのページに関しては）直るのですが、あまり実用的な対処方法ではありません。

I can confirm that after last FF update this extension isn't working at this moment.

The addon is very customizable and works as advertised, but there's one big problem. On websites with lots of autoplay videos, like Reddit for instance, scrolling through will become very laggy and skip around repeatedly, losing all smoothness. This doesn't happen with Firefox's native smooth scrolling or autoscrolling feature. I'm on Linux by the way. Not sure if that's relevant.

Poor performance with smoothing while on Linux.

When you scroll to the very top. page bounces back. Please add an option to disable this move

Generally useful, but
- does not work on all pages
- settings need description, eg. labels for the diagram, or the colored areas. (Yes, it its possible to figure them out eventually, but this not exactly intuitive and user-friendly.

With these issued fixed it would be worth 5 stars.

Doesn't work on all sites and appears to be limited to 60Hz.