Does Azo really work?

Azo is the cranberry pills that are suppose to prevent utis/ help bladder pain. I've been prone to utis since I started having sex, I pee before and after, drink plenty of water, etc etc. I thought I should try taking the azo pills everyday now. I had a doctor tell me that I need to be careful because cranberry does not treat a uti, only prevents. So I need antibiotics at the first sign of symptoms. There are 2 kinds of azo pills, one that just eases pressure off your bladder (seems like this would only help of you already had a uti?) and one that is just general urinary tract health, so I think for prevention I need the second one. Has anyone had any good experiences with Azo? Which kind of Azo did you take?