Apparently a St. Louis based news crew did some investigative reporting on computer repair services:
http://www.ksdk.com/news/news_article.aspx?storyid=131998&provider=top I'm not sure I agree with their methodolgy...which involved jumpering the hard drive. But the results (and the statements from the companies after the fact) were instructive.
I'm glad I know competent people who can fix my computer for me :-)