I'm in education, not public health, and live in a place where distance education is the only option for an advanced degree. I've done a master's by distance for certification purposes and really didn't learn much. My experience was that the quality of courses varied tremendously by instructor, and there was no way to select alternate courses that might be more rigorous. While a lot of breadth could be accommodated, the online medium really made in-depth discourse rare. So my thoughts would be to do online if there's a specific course you know is good or if the degree is just a hoop you're jumping through for another goal, but to go in person if you want to develop advanced skills or knowledge.