Good Companies To Work For = Good Investment?

Fortune Magazine just published the annual list of the 100 best companies to work for 2006. To check out the full list: Click here What's interesting is that my portfolio contains 4 companies on the list. They are: Genentech - #1 on the list, Amgen - #39, Microsoft - #42 and Genzyme - #51. So back to my question: Are companies on this list good investments? I think so... If I have some free time, I'll look at the returns as a group for the 100 best companies to work for and compare it to the return of the S&P 500. I bet that the 100 best companies will generate a higher return than the S&P 500. Just a hunch...