How are the cities in the Bay Area different from each other?

My boyfriend might possibly be moving to the Bay Area to work in San Francisco, and in the next 3 weeks he would have to find an apartment.

He’s trying to get a feel of what area would be best to live in, but right now he doesn’t have a clue where he should start looking. Also, I don’t think money will really be an issue, we’re just trying to find the best cultural fit.

So, my question for you all is: how do the cities around SF differ, and also, how do the neighborhoods/zones in SF differ from each other?