2.5 stars. This extension is the only one of it's kind that works at all for the current version of Firefox, however, the developer should compare it to Chrome's extension "Font Rendering Enhancer". There, there is only one setting. The contrast is increased without distortion and all colors are kept including the color of links (it seems to me that the extension causes Chrome to render all the text on a page twice; first where it belongs and then again shifted to the right less than one pixel, and it's adjustable). On the other hand, this extension for Firefox, known as Legibility is awkward and at best will make colored text monochrome (as well as text intended to be grey). But, since it is the only practical solution available for Firefox text, I'm giving it 2.5 stars.