Works good. However sometimes it slows down the browser when using YouTube for example.

Excelente, sencillo y con opciones muy bien pensadas

Was working excellent some time ago, but recently stopped working for basically half of all websites I visit

Worked great previously, lately has issues with REALLY bad stuttering when scrolling through some web pages, to the point of unusability with the addon enabled.

On Firefox for Android

I only wanted to put google calendar in dark mode, and it works perfectly, I'm very satisfied!

good but sometimes when i turn off, my firefox browser theme goes from dark to light or vice versa.

Firefox dark mode made a couple sites unusable but Dark Reader seems to have solved that with a nice contrast setting without losing images or darker items on a page.