Tapfuze's $3 () is a simple yet useful utility that serves a single purpose--providing you a way to easily toggle your monitor's brightness setting. When you install Shade Control it appears in your menu bar, represented by a lamp icon. Click the icon and you see a slider for adjusting brightness up and down as well as a toggle command.
With Shade Control toggled on, adjust the brightness for your current environment--you're working in a dark room and don't need the monitor at full brightness, for example. When you're ready to return it to its "regular" setting (as configured by the keyboard brightness controls or Display preference setting), just choose Toggle Off from the Shade Control menu. Simple.
Could it do more? Sure. It would be great if you could separately control the brightness of multiple monitors. It would also be nice if you could invoke a keyboard command to toggle it on and off instead of having to click a menu command. And although the description claims that you can use the Mac's arrow keys to adjust brightness up and down after clicking on the Shade Control icon, I couldn't get it to work.
Still, if you want to quickly switch from one brightness setting to another and would rather do so without using the Mac's brightness keys, this is a reasonably convenient way to do it.