For overall adjustments of colors on your monitor in non-colormanaged applications there's nothing terribly wrong with adobe gamma. It adjusts monitor colors via videocard LUTs.
However the main idea of color management is measuring the display's output (not adjusting it) and providing colormanaged applications with this information. Colormanaged applications use this information to adjust the RGB numbers they send to a device. That way you achieve device-independant color, no matter how your device looks in non-colormanaged applications. These two kinds of apps display colors differently.
You can also adjust the overall appearance of your monitor using a colorimeter-based calibration solution if you have a reason for that (such as make different monitors look similar in non-colormanaged applications), and some of the adjustments may be done via vc LUTs. A colorimeter-based software will give you a closer match than those visual gamma sliders cause it knows exactly what display colors look like. But it's a separate and to some extent secondary task. The main thing is measurment.
<edit> Usually those two tasks are referred to as "calibration" (adjustment) and "profiling" (measurment). With Adobe Gamma you can change how monitor looks like but you don't get an accurate profile of it.
