If you care about how someone dresses when you hire them, odds are you're using bad criteria for your decisions. That's not to say that you can't get great people, but you're probably paying over the odds for them, if "dresses nicely" is one of your factors for selection.
I think I will hire better if I dont care about dress code - I think odds are better that I will find a good hire if one of my criteria is not "do they own a suit or a dress".