Like any big city there are great, safe neighborhoods to live in and some not so great areas. Some of the areas that get more sun and are nicer are The Marina, Russian Hill, Cow Hollow, Pacific Heights, Soma and then good family areas are Noe Valley and West Portal. The best advice I can give you is to fly to San Francisco and spend a long weekend there. Visit the different areas and go to restaurants, shops and parks and just start talking to as many people as you can. You will hear the good and the bad. After visiting these areas you will feel it in your gut which one fits you best. San Francisco is a great town, it's very diverse and there is a lot to do. Have fun!