Decent, but still has plenty of room for improvement. One particular thing I'd like to see is the ability to customize the choice of colors used. For example when I use this extension on Facebook, it makes the text in the edit boxes light gray on white. This is very difficult to read, and hurts my eyes, which the purpose of this extension was supposed to be easy on the eyes. Perhaps you can make an options page with a color picker for each color used in the current page theme override.