Color versus Black and White in direct mail - what's your opinion?

I've always used color in any just listed, just sold and expired mailings that I've done, but I'm wondering if any of you are getting response from using black and white print instead?  In an effort to make my pieces stand out in the mail, I'm thinking about going to black and white because everything else is in color.  If you have an opinion on this, I would love to hear it!  Also, are you getting as much election-related stuff in your mailbox as I am??  I get 2 or 3 postcards a day!