Yeah, the main series can be very dry, and most of the games have an unforgiving difficulty as well as being, for the most part, kind of depressing to playthrough since more often than not some, if not all or most, of your human party members leave you and have to fight them later depending on which path you take.
Persona 3/4 from what I have seen have a nice mechanic, but it feels a bit to bubblegummy for me at times.

And yeah, some of the things in the Megaten brand can either very good or very bad.
But do not mention Persona: Trinity Soul. We do not speak of it,