In the policy world, the name of your school matters a great deal. Also, so do your connections, so a school with faculty who have connections would be key. If you want to do policy, either degree can be fine to get you there, it really depends on your background and the areas you are interested in pursuing. Look up analysts and lobbyists in the fields you want to be part of to see what kinds of schooling they typically have. I'm interested in policy and many of the types of work I'm interested in (civil rights, education) want people with law degrees, which I think is because there is such a heavy cross-over with constituitional issues that policy degrees would not teach as in depth. But in some fields, policy degrees would be better. However, I think first and foremost the name of the school will carry you in the policy world so it probably makes sense to apply to both types of programs and go to the best school you get into - though consider money as well because policy jobs often don't pay well.