I think both areas can be rewarding and give one a great sense of personal fulfilment. At the same time, however, it is extremely difficult for a recently graduated law student to start out in either field as a career. I'll state confidentally that it is significantly harder to get a job...
Yes I work at AAR.
It is difficult, with any degree of confidence, to give you "tips" about what will or will not get you a job there - afterall, even after being hired, you are never told on what basis you were hired.
I can tell you the party line: "Imagination, Interests and Intelligence"...