Excellent job of darkening. 4 stars only because: I can not (afaik) darken, for example WWW.google.com but NOT DARKEN WWW.google.com/maps. I want most sites normal so I use the INVERT LIST ONLY. Abilitiy to add subsites would help.
Revision: downgraded to 3 stars. Impossible to find documentation for the 2 short-cut keys, Alt/shift/A and Alt/shift/d.