We talked about this before in this thread and if you reaaaaally want to, you can go back and find my and others posts, but basically
The classical consensus was that Persona 2: Innocent Sin was already one of the best games in the entire meta-franchise of the Megami * games when it came out. I personally feel it still holds up just as well today.
In fact, I consider Persona 2 Tsumi to be the best Persona game, with P4 a bit behind it.
Persona 1 is mediocre, to be frank, though there are a good amount of unimportant references to it in the P2 games I wholeheartdly recommend skipping that fucker
For the record, the second half of the Persona 2 miniseries, Persona 2: Batsu/Eternal Punishment, is great but not even close to how good the original Persona 2 is.
Persona 1 and 2 are more traditional JRPGs, by the way, with an emphasis on narrative and characters. Persona 2's is probably one of the best casts a Japanese RPG has ever had. There is no date/life sim elements at all.
There's your short answer.