I've only played Persona 4. It's the only Atlus game I've played. With that being said, I really loved Persona 4 and I'd love to be able to play another. I guess it depends on who buys Atlus, if Nintendo or Sony buys them the chances of it being on PC are nonexistent.
As a huge fan of Persona 4, I was actually pretty let down when I tried Persona 3 on the PSP. The dungeon doesn't really seem to change much and so you don't have the zones with distinct personalities. The story also didn't grab me the way Persona 4's did. The characters were okay but I wasn't crazy about them either. Except when I got a puppy. That was great.
I'll definitely pick up P5 after having played so much P4, though.