That's a tough call given that they are going to provide it tuition free. MCAT is solid and with a good upward trend you are bound to have luck - especially at state schools. How are your ECs, volunteer, etc.? If they are solid you may as well apply. I guess it really comes down to whether or not you really want an MPH education. If you are interested in it and think it would complement your career as a physician, then go for it. If you are considering it for a GPA boost, then I wouldn't be so quick to pursue it.