Norcal: that is a tough call. I think from either one of the two schools, you are going to have to get excellent grades (top ten percent) to have a shot at any kind of firm job in SF and you'd probably have to do pretty damn well to get a public sector job in SF too.
USF is tier three and there are far too many other top notch schools in the area (in addition to people coming to SF from all throughout the t-14). To get a job in the bay area in my opinion (go look at the nalp data for USF and see what it says...talk to career services at USF...call Dean Nailon, the career services director at UA to see what she says about jobs in SF) it's going to take good grades and effort on your behalf.
It's definitely not impossible to get to SF from UA, students from my class are going to both NYC and SF to work for big firms this summer. It has a lot to do with what you put into it. In my honest opinion though, going to USF with the huge debt load you will take on (or did they give you money??) is a risk I wouldn't take when you have a much more solid option like UA. UA is a very solid tier one that will give you good options in AZ if you do ok and great options in AZ, CA, NV, and surrounding states if you get excellent grades.