Advantage is a leisure oriented car rental division of Hertz. Cannot speak to San Diego, but I have rented from them within the past year in Denver and Seattle at 50% discount over Hertz's on airport costs. You can use a Hertz CPD #'s (e.g. USAA) when making the reservation to get corporate discounts. A little bit less convenient than a Hertz gold card experience, off airport usually, (although not at DCA for example); in Denver the agent tried the usual upsell by saying she would put me in a tiny Fiat or equivalent, and I told her I had not tried one, and that might be interesting to drive; of course they didn't have any and I was in Toyota Camry instead at no charge.
So can't guarantee the experience, but you might do fine.