This is a difficult decision and realize that this is your life so take any anonymous internet poster advice on this board or others mine included with a grain of salt. With that said I am an attorney and have some experience, but I have never been to Boston or set foot on the Georgetown Campus, but I think there are some universal principals any 0L should consider when choosing a law school that I will outline below.
When choosing a law school I believe a student should consider the following factors in this order (1) Location of school. (2) Cost of School. (3) Personal Feelings about the School (4) Last and least U.S. News Rankings. (5) You should also be aware of the reality of legal education and all of these I will outline below.
From your post it appears you are interested in working in the New England Area and I assume that you are either living in the New Engalnd or want to live in the New England Area. This is important to know since whatever law school you attend you will be spending a minimum of three years of your life there and more than likely the majority of your legal career will be spent in that location.
So you have to ask yourself where would you rather live for three years and maybe spend a substantial part of your life D.C. or Boston? Both have different pros and cons, but you have family and friends in Boston that will make your law school experience easier and also remember that whatever shcool you attend it does exist in a vaccuum whatever friends, family, connections you have in either location is something to consider as is the culture of each City. Which one do you feel more comfortable living in that is a question only you can answer and especially over three years you are likely to get an apartment you like, enter a relationship, etc and you will likely stay in the City you attend law school. Again, what City you like more is a question only you can answer.
Georgetown is 46k per year in tuition while Boston is cheaper and 15k improves the cost factor even more. However, one thing to look at is the condition on the 15k scholarship I am guessing like most law schools it requires a GPA requirement or you to attain a certain class rank. The most common stipulation I see is a 3.0 GPA requirement, which most 0L's think will be a breeze to attain, but unlike undergrad law school has a mandatory curve and generally only 35% of the class can have a 3.0 GPA. Again like most 0L's you and 100% of your classmates will sincerely believe they will be in the top 10% and there is no way you could possibly finish in outside of the top 35%, but students at every ABA law school are smart, hard-working, and motivated. So there is a 65% chance you will not finish in the top 35% and you will lose the scholarship for years two and three. So if this is scholarship is an option ask as many question as possible regarding the conditions.
Then look at the cost of both schools and consider how much debt you are going into. These are large numbers and if there are favorable conditions a total of 45k over three years and the cheaper cost of BU tuition is something to consider, but again it is a question you have to answer for yourself.
3. Personal Feelings about School
It sounds like you enjoy the prospect of attending BU and I can tell you from my experience as a OL and participating in mock trial competitions that each school has a culture to it and some you will like others you will not. Again that is personal I know there were some schools I loved and others I hated, but you may have loved what I hated and hated what I loved. It is three years of your life so make sure you will enjoy the school visit both campuses, talk to students, professors, and see how you personally feel about them don't listen to internet posters, magazines, etc it is your life and nobody knows better than you what environment will suit you best.
4) U.S. News
I personally think rankings are absolutely irrelevant as it is a for-profit unregulated magazine offering an opinion, but Georgetown is a school that has a national reputation and can open the door to BigLaw, Federal Clerkships, and other opportunities that may not be as easily available from BU, but are those positions you are even interested in? If you want to be a public defender, D.A, or City Attorney, Family lawyer, or something else then paying the extra money for Georgetown doesn't make any sense. However, if you aspire to join up with Cravath, or O'Melveny & Meyers or some other firm then I think Georgetown will provide you with more opportunities than BU will.
However, for the majority of legal jobs they want you to pass the bar. Georgetown will give you a leg up in many positions, but there will be some positions that will think your overqualified. Again, I don't know your professional goals, but that is something to consider.
Reality of Legal Education
At BU, Georgetown, or any other school you will learn the same thing. Your first year will be torts, contracts, civil procedure, etc and you will read Supreme Court cases and they do not write seperate opinions for different schools. At the end of your three years whether you attend BU, Georgetown or any other school you will then likely use BarBri or Kaplan along with every other law student in America to pass the bar exam. If you succeed on the bar you will then be given a law license.
Choosing a law school is a difficult prospect and certainly Georgetown has a prestige factor that is something to consider, but listen to your gut when visiting the schools, consider costs, and what city you want to live in. There is no right answer and both are great options congrats on your acceptances and good luck whatever you decide.