I like this add-on. It works very well. However, it sometimes warns me that Firefox is slow, especially in Gmail, and I recommend not using this add-on in Gmail. Fortunately, this add-on allows you to create a blacklist of sites, so you don't have to turn off the add-on feature every time you open Gmail.

Postscript (2023/06/23):
In this add-on, some image characters (?) are displayed as characters instead of images. For example, when you open https://translate.google.co.jp, you might see characters like "swap_horiz" and "star_border". The reference image can be found at the following URL: https://imgur.com/gallery/vsjC8eL.

Love the idea but it's janky. Some sites look odd, which is fine as you can disable per site, but i currently can't as the shortcut isn't working and the menu has stopped working properly. Also causes a slight delay in loading sites that it's turned on for.

It crashed and make the sites loads more than normal, it takes too much resources that it needs too

Edit: Some sites have elements hidden while in Dark Mode. This has given me problems. I can edit the theme for such sites BUT - a suggestion: when editing/creating a theme, please make the default to only do so for the CURRENT SITE. "All sites" should be explicitly chosen by the user. Thank you!

This is a great add-on and I keep it ON by default. One important improvement for me would be this:
The default behavior for text fields (e.g., username/password fields) gives me yellow background with white lettering. It would be better to have either darker lettering or darker background. As it is, it is very hard (next to impossibile) to make out anything.
Other than that, perfect! THANK YOU :-)

Делает сайты темными достаточно корректно. Но при открытии любой страницы (даже уже темной), на экране появляется сначала белая страница, потом уже темная - это очень раздражает, особенно ночью. Ну и естественно расширение замедляет загрузку страниц.

Works great and deserves it's 5 stars.

works as one might expect, the auto detect dark mode feature is bit slow but that's a minor problem

I have been using this for years on Firefox and on Chrome and it works very well. It makes things not hurt eyes.

Excellent job of darkening. But, as I use it more and more, I find more I would like improved. Now 3 stars, 20251107.
1. I can not (afaik) darken as subsite, e.g. www.ebay.com/itm. I can only darken the entire domain.
2. I can not add ANY entries to the SITE LIST. All I can do is change the few that are there.
3. new (20111107): I just discovered that Dark Reader is darkening not only the web site, but Firefox's control areas. (The tab bar, the location bar and the menu bar, all of which I display.) This is HORRIBLE. It makes some fields in these very difficult to see. Sadly, all these fields are not named GUI controls, which may be the reason. Particularly annoying since I spend much time customizing ALL the colors in those fields with custom .CSS.
4. The addon is very difficult to manage. There are essentially 2 ways.
A. Left click its icon on the location bar. This opens a Dark Reader control panel.
1) I can't scroll it and can't seeall of it. I use a 150% Windows magnification level. that's probably why.
2) I have no idea what the SEPIA value does
3) THIS CONTROL PANEL DOES NOT ALLOW ME TO CONTROL ALL THE SETTINGS I CAN CHANGE.
B. Right click its icon and choose "manage extension"
1) here we find controlling the shortcut keys
Why do not A and B include all the same stuff?
5. The documentation for this addon is only fair. (Otherwise, I would have learned all the above. I READ DOCUMENTATION for almost everything)
This include operation and use of the addon
and info about recent updates.
6. Functionality: The addon does a POOR job of handling shades of gray (actually all colors, but this is the most common example since many websites lack interesting use of color.) It says it darkens bright colors. But, it should also then brighten light color to retain contrast. Webpage areas in shades of shades are often turned unreadable.
7. Money
I would contribute, but find no way to do so. All I saw was a "buy it", but I don't even remember where I saw that.

the 3 rating is muchly due to the fact that some of these issues I have mentioned long, long ago.