I visited both today for the first time. I definitely recommend Reef Hot Spot. The owner was very nice and accomodating as I took my time browsing their live stock. The store's only been up and running for a couple of months and open to walk in for a couple of weeks, but their pricing and selection is pretty impressive so far ($30 for Med Croceas, $40 for larger for example). He says he plans on concentrating on SPS as they are his personal favorite. I picked up a couple of nice rics and a favia.
Medusa was ok. As others have stated, prices are pretty high ($20 for percula & common firefish). Their round coral display tank is nice with some very nice teardrop baby maximas, but other than that nothing special.
I will definitely continue to visit Reef Hot Spot whenever I'm on the westside.