Yeah this has been discussed..
here is my synopsis.. all have different strengths and weaknesses.
Those requiring higher board scores are Christ and U of C. I dont know about NW.. Board scores more in the avg range are needed for Res, Cook, and UIC.. The details can be found in a prior thread. If I am sufficiently bored during the sub-i today ill try to find the thread for you.. Im on short call so who knows...