looks good, but slows down firefox until it's unusable because my CPU (i7-6600U) is utilized at 90-100%

GOOD:
(1) I've not noticed any slowdown at all on page loading in Edge, Firefox, Chrome, Opera or UR browser for Pro 3.2.1
(2) It appears to blank out the Google Ads box on a lot of pages when using Dark Mode.
BAD:
(1) On some browsers' addon pages, I see a lot of comments about not knowing the cost of Pro (which is $9.00 p.a./ 2c per day). That should be headline, not something you have to seek out.
(2) On Gmail, the options after opening an email disappear. Not a big problem - just right click and 'back' arrow.

Amazing . I am so happy to have stumbled across this add-on. Initially I was looking for a dark solution for Dropbox Paper(which it is great for), but it also solved a long time issue I have had with dark mode workarounds in jupyter notebook. Also works great across all other webpages. So much value IMO even as a paid add-on. Cannot fault it yet. Great work.

It is incredible add-on. I'm using it on all browsers and it is a true game changer. I don't get it how can someone rate it down, just because it is paid + it is obvious that it is paid add-on...

It should be made clearer before installation that it's not free. Removed.

La primera extensión de pago que me encuentro en firefox... espero no volverlo a ver nunca mas
Recomiendo:
https://addons.mozilla.org/es/firefox/addon/darkreader/

This add on works pretty well for Chrome, but is completely unusable on Firefox. Aside from horrible performance, it also causes issues with Ajax calls and other extensions.

Horrible on Firefox. Makes all websites slow and unresponsive and constantly crashes Firefox. And I have to pay real money for this privilege? Pass.

Extension payante !!!

Bagus Add On ine. batur.

Just Excellent!!!

as many said slowed down and made it unusable on several web sites, I thought it was good on Facebook too until I got to my home computer and it was awful and it is a far better equipped computer... I'll wait for an update or a built-in solution. (on Facebook it turns all the emoji black)