Hopefully, it isn't too late for some input from a current UCLA MSW student! Having just finished my first year at UCLA, I feel compelled to provide some honest information regarding the program to potential students; I certainly wish someone told me coming into the program. UCLA is currently going through a pretty massive overhaul of their MSW program and it has been showing in the drop in the quality of the faculty. Additionally, a significant amount of the courses are very superficial and it often feels like we are given assignments that are too elementary. I have a lot of worry that many of the students will leave the program ill-equipped for many of the monumental obstacles that are ahead. In the current state, I believe that the academic portion of the UCLA program provides minimal substance for those individuals who have had a very good psychology education or has spent time working in human services. However, the field placement portion is an extremely helpful learning experience and UCLA tries pretty hard to place you in a situation that WILL allow you to grow. Not everyone felt comfortable in their placement, but you don't grow much if you never step outside your comfort zone.
In terms of your specific situation, you should understand that if you do attend UCLA, you will most likely not be placed in the West Side. If that is a deal-breaker, that should make your decision easy. However, I feel like you are really limiting your potential for development as a clinician if you don't try some things outside of your comfort zone. It sounds like a bigger factor in your decision making process is the geographical location. First off, from what I have heard, I think that the California licensing standards for LCSW's is one of the strictest in the country. What that means is that if you go to Boston and decide to return to CA, you might have to take some additional measures to retain your license. I'm not sure exactly how it would go if you went from CA to Boston. In terms of your career goals, if you want to move to the Northeast, it would benefit you greatly to attend BC. You would have a head start in getting to learn about some of the agencies in the area, and you would be able to start building networks through your school, classmates, and placement.
Lastly, I'm sure the relationship is something that is weighing heavily on your mind. I think that is something that you need to consider carefully, and think about how it stacks up against the pros and cons of attending BC. I have tried to add some honest information about the state of the UCLA program and my view of the BC program. I think it will be up to you to ultimately decide how much the relationship means to you. Best of luck with the decision, and feel free to ask if you have any other questions about the UCLA.