McKinsey sells ego-gratification to CEO's (oh, and the occassional "political access" tidbit).
It's almost always good when your competition hires them (or Accenture, or a variety of other such "consulting" firms), as it usually means that you will have no trouble outperforming them in the forseeable future (one major exception, of course, revolves around how they secure political favors in and out of the U.S., however).