Porites porites is a Caribbean coral and therefore not available for collection. It is therefore usually not available in the trade. It would be possible to get it on aquacultured rock from the Keys, though I'm not sure if that species has shown up. We've got some P. divaricata here in the lab, which is a sister species. They're pretty undemanding and seem to be doing fine. We've had them for a year and a half or so, and just recently got some decent light on them so growth has picked up.
There a several similar-looking Pacific species that are usually available. Given decent conditions and relatively bright light Porites is usually undemending IME. Most of them really do prefer and need brighter light to thrive though, and ideally stongish water motion.
cj