I am currently around $70,000 in debt, but with an interest rate of <.5%. As such, I am not that "scared" of the high debt I have accrued already, but I certainly would not go anywhere if I need to borrow more than $10-20,000. I have taken funding into account while applying (as such, HKS was quickly off the table) since I am actively pursuing a career in public service. If you are not, you may feel free to take some more risks, but be careful.
Speaking from nothing but personal opinion I find MBA to not be "that much more qualified" than many other masters (quant-MPP, Econ, engineering). I would assume the ease of finding a job in the private sector with an MPP relies upon the focus of that specific MPP, simply put.