Yes and no. I know of two schools in the San Francisco area. The cheaper, shorter one seems to send people to the same externships as the expensive, long one. Drawing blood from real patients is where you really learn stuff. Everything else is just prep.
I suspect that working at an HIV ward would look better than at an uptown clinic. I know that working in a place that serves a lot of IV drug users will be really frustrating, but will also sharpen your skills REALLY quickly.