For sure! I unfortunately don't think that all of this will apply to everyone, but here was my logic. It pretty quickly came down to Columbia and JHU for me, and that's because both are closer to my family - I'm from the NE.
From there, the reasons I preferred JHU were as follows:
1. JHU over two years was significantly cheaper than Columbia from cost of living. Tuition was comparable, but rent is much cheaper, and "doing things" (meaning having fun on weekends and things) is MUCH cheaper here. Also, Baltimore is not that exciting of a city - there are definitely things to do here but it's no Manhattan. Therefore, not only are things cheaper in general, there are less things that I want to spend money on here anyway. This also helps keep me focused, I think.
2. JHU has a track specific to my area of interest - aging. Columbia didn't. NOTE - looking back, I actually don't think that this is that important. I don't think that the elective coursework here is that different from Columbia's. As long as some people are doing the research you want, the "label" on your degree means little. Employers are not looking for your concentration/major so much as your general research skills - which you'll get in any concentration - and your actual research experience, which you get outside of class. This is all IMO.
3. My impression of the student body was that people at JHU tend to be a little bit older and have more experience (mostly because of the two-year work requirement for the MPH program, and the relatively large number of PhD students), which I liked. That's not to say I dislike people who come straight from undergrad, but I think that the vast majority of people here have a really good idea of what they want.
After almost a year of school, I do think the actual training you will get will be similar between the two schools, so I wouldn't worry too much about that. One benefit of NYC that I can see is that there is certainly a larger variety of opportunities within the city after you graduate.
Those were the main things. If you have more specific questions, please let me know!