My personal feeling is that Pie charts take up too much space for what they do, are difficult to annotate properly, and make you have to carefully look at or even study the chart to figure out if something is out of spec. Horizontal % barometers make more sense to me but, even more than that, a nice table of values with Red, Orange, and Yellow highlighted cells is extraordinarly easy to recognize problem areas in a very quick scan, provides all the information you need in a comparatively very compact reporting format, and, my most favorite reason of all {drum roll please}, doesn't require me to even go near SSRS.

If you do it right, it'll even help you find "lost" CD's and DVD's that you left in a machine somewhere. I color those Green just to make them obvious.