I grew up in NY, and I know Boston very well. Being from the north, I never thought I'd like Atlanta, and I had never visited until after I was admitted to Emory. I can say that I absolutely love Atlanta, and was surprised to like it so much.
Atlanta is a city where you'd be greatly advantaged to have a car. Car aside, it's much cheaper than Boston, the weather is quite good, the people are friendly, and there are a lot of cool neighborhoods. The class at Emory is very small and cohesive, so you'll have a lot of friends to go out with on most nights.
I'm not trying to post an advertisement for the school. I do think you should visit both schools if you can, get as much information as you need, and make a decision on the school that fits you best. If you have any specific questions though, do feel free to reach out. I'm studying abroad this semester, so I'm not physically on campus. Our welcome weekend is going on right now, so please watch whatever webcasts you'd like, and best of luck with the decision.