@hotpaws are you able to get any financial aid from the school? scholarships?
I am just going to comment on the Hong kong part as I have never been to baltimore or atlanta but I have lived in HK before and regularly visits. For me personally, I think it is a great city. The food/culture is awesome and things are cheap and from what I understand, HKU is a very prestigious school, probably the best in Hong Kong (I don't know about now). However, I think a part of the decision making part will also be based on where I want to be after graduate school. Are you planning to stay in the US to find a job or move back to Asia?? If you get a phD are you planning to teach in the US or Asia??