Pros
Mission; telework up to 2 days a week if your job is suited to it; federal benefits; can commute by car; some green space around
Cons
Parking situation on main campus (if you go out and try to return before about 2:00 you may not get a space on your return); traffic in the area; noise from constant construction; no restaurants, drugstores, etc., nearby to walk to; many top management positions held by people who are smart scientifically but lacking on the people-skills side; it is possible to just become "part of the woodwork" if you stay a long time while management's favorites advance, receive the interesting assignments, etc.; expect that your focus is science and how much you also focus on the health care aspect may depend on what part of NIH you are in and what your job is.