This Extension provides excellent dark themes on almost all websites. But when I visited sites such as redhat.com/en/blog/..., my CPU usage went all the way to ~90% (a fairly new Intel i5) and RAM (4GB) continued being filled up until the whole system crashed.

Works on almost all sites. Loads well, though sometimes there's a flash of the original site before it loads.
Doesn't work on the firefox site though.
Overall, very useful.

This addon has gotten much better but in the last week or so it stopped working on addons.mozilla.org. I have all the necessary about:config changes made to enable it to work with this site, but it just...doesn't. Was working fine before.

Slows down sites to the point of being unusable. No read the manual section. Counterintuitive settings.

Almost Best Addon Everr!!

Thanks !

removed this add-on because I started getting Fake iPhone X for a $1 scam pop-ups in the Firefox browser.

It is difficult to create an algorythm that would give the optimum result to every page on the net I imagine. That is why respect for the undertaking, thanks for delivery. The addon would greatly benefit from an integrated user feedback feature that just reports which site is with which mode is not working to arrive at an overview.