It is great, but stick to the static theme generator or it can slow down sites considerably.
It is very noticeable on duckduckgo:
clicking a result link and then going back to ddg takes seconds longer with dark mode on, which is ridiculous.
Dynamic mode should not be the default until this is addressed.

Changes all websites to dark mode very reliably. There are occasionally smaller issues if pictures are in the background (text becomes hard to read).
Easily to revert to original. Very low performance penalty, which is worth to have all pages in dark mode.

It's a must to save your eyes! Some sites eventually break, however the extension can be easily deactivated specifically for those.

May the Dark Force be with you

works immediately, does exactly what I want, and has the best configuration settings! :-)

Desde que lo agregé al navegador lo negro se ve de color azúl oscuro, ¿que pasó?

Dark Reader addon has a serious memory leak issue. This problem is affecting users for quite a long time.