I have essentially the same question but didn't want to make a new thread. I just graduated and am starting my gap year and am trying to do some volunteer work. Hospital app is asking for two references. I have one spot left and I'm deciding between my manager at a bar/restaurant I worked at for two summers and a professor/head of a clinical research program I did. I think the manager probably knows me more personally but the professor can attest to the kind of clinical experience I had in her research program. Which do you think I should chose?
Also if you don't mind me asking OP, how did things turn out for you?