Rated 5 out of 5 stars

Colorific brought me here, and this add-on is much better IMHO. I've been searching for a decent dark global theme on userstyles for days, and this add-on is the only one that actually does what I want -it doesn't hide pictures, doesn't remove background images (creating transparency and overlapping text), and is quite customizable.
In the future, I'd like to see a custom "transparency factor", which defines how intense the presets should be, or even better: a presets editor (e.g. make the "Blue on Black" backgrounds darker while keeping the text intact).
Also, I've seen that you've got the auto enable feature planned, but is there any workaround to auto enable it for now?

This review is for a previous version of the add-on (3.2). 

Thanks for letting me know your opinion and wishes. Currently, there is no way to auto-enable Color Transform or Colorific, but I have started to work on this feature. The presets editor is also on my to-do list - it will probably be implemented as a sidebar with sliders for the coefficients of all effects. Transparency options and a faster approach to image effects are also on my list. Please have some patience :)