Isn't the JHU's MSPH a "Masters of Science in Public Health"? Personally, I'd go to JHU in your shoes just because the global health bench at JHU is pretty deep. Just being around faculty that are interested in global health epi, and actually distinguished in the field I think would be a bigger help, in terms of figuring out what sort of job you might want, and what skills you'd want to bulk up. Just doing an MS in Epi at a school not super distinguished for global health work seems like more of a shot gun approach, versus with JHU you could get terrific exposure to exactly that field, and figure out what skills to focus on.