Although I don't know of anyone with an MPH in health policy/management currently working in the field, I sorta do agree with the above statement that this is probably the best area to go into if you want to make money---especially right out of school (maybe epi as well). The only person I knew in health policy/management while in public health school, decided that the opportunities (and pay potential) just wasn't there so they decided to pursue opportunities outside of public health once they graduated.
As someone who has been working in the field for several years, I will say that at least for me, it has been difficult (as far as pay and advancement is concerned) just having the MPH alone. I took the health promotion/health education route and found that once I graduated, many of the opportunities that I thought would be open to me, began to be taken by people with duel degrees such as RN/MPH's. Remember there are a whole lot of people who had other careers who are going back to get MPHs so the degree alone, in my opinion, is not nearly as powerful as maybe it once was. Also the people that are really calling the shots in a lot of federal agences such as CDC, HRSA, SAMHSA, etc. have doctoral degrees (namely MDs) in addition to their public health degree.
I am sure that there are plenty of people out here who are doing well financially and so on with just an MPH but many of those who are have had to stay in their jobs (namely the federal government) for many, many years in order to get to their levels. My experiences with just an MPH have prompted me to go back and get another advanced degree.