I've been using Color Schemes for a couple of weeks and have been very pleased with the application. It makes "playing" with colors fun! It is very easy to select a main color using the RGB sliders, decimal values, or a color picker (any of the built-in pickers seem to work). Color Schemes does all the hard work of finding complimentary colors in "automatic" mode. Then, by clicking on the color picker button, one can tweak the complimentary colors. Finally, I'd like to say that the developer, Paul Young, has been extremely responsive to suggestions.