The first movie was okay as an adaptation, but not that great as a film. The second movie was better as a film, but took more creative liberty as an adaptation. The third movie is just a mess. They should have called it “Ryoji is here guys, so let’s make this movie about him now! Except where we need to jam in fights because I guess there was a plot we need to adapt.”
Just like my post on the second movie, there will be some spoilers. So play Persona 3 FES first if you’re looking to avoid them.