The only Persona games I've played is Persona 1+2. Both were pretty interesting but I haven't dedicated too much time to finishing them. Persona 1 was excruciating and Persona 2 had the highest damn random encounter rate I've seen since Fallout 2, FFII, and FFV. But yeah I like them. One thing that was interesting about Persona 2 was summoning new Personas. Though I saw it as a bit complex at time. But luckily they improved the negotiation system from Persona 1 and made it far better.