Has almost all the features one could expect

I transitioned from Dark Reader to Midnight Lizard. The customization is much easier.

My biggest wish is to change the PDF color's in Firefox's built-in viewer.

So far this is the most effective dark mode add-on I have used (switched from Dark Reader due to it frequently defaulting my FF Theme), though maybe not the most efficient with some sites/pages have some CPU load runaway (CPU used i7 4770k).

This addon does magic. But it's resource demanding.

好

One of my favorite add-ons in Firefox and a big reason that I use Firefox to begin with. Saves my eyes from the bright white glare of the modern internet, which is hamstrung by and simply cannot get out of the mindset of using black text on white paper, which dates back hundreds of years. How is staring into a light source a good thing for the eyes? I wear glasses now because of this.

Fantastic amount of customization available within the extension, no programming experience required! No need to mess with it if you don't want to though, default settings and given options work great and make for less eye strain

The darkening works fine, but interferes heavily on page loading times. For instance, when trying to create a new event in Google Calendar, this extension adds about 2-5 seconds between the instant I click on an empty bit of calendar and the instant the new event dialog pops up. When I want to click on the X button to close that dialog, I also have to wait a few seconds before my clikc is registered.

I installed the competitor extension Dark Reader and I don't have this problem anymore.