So far, I own every iteration of every SMT game to come out in America (including the PS1 Personas that are very hard to find). Unless you count Jack Bros for the Virtual Boy, because it's not an official SMT and costs a solid grand usually. IMO, Persona 3/4 and Devil Survivor 1/2 are by far the best. IV wasn't bad, Strange Journey was pretty good, as was Nocturne. I could never get that in to Digital Devil Saga.
I'm amped for P5, Q and SMTxFE. I bought a Wii U just for when SMTxFE comes out. Two of my favorite franchises (maybe the only two I've played every game in) combined. Also, I really hope they do release the Devil Survivor 2 3DS remake eventually, because Overclocked was so good.