Alright here we go, my favourite Persona characters in order:
Junpei Iori - For most of Persona 3 I hated Junpei because his hobby is bitching about not being the protagonist; however late game Junpei has some of the best character development and is awarded with an amazing event in which he gains his ultimate Persona. 20 / 100
Yukiko Amagi - I really like all the Persona 4 characters but Yukiko is probably the worst party member. When I first started playing Persona 4 she ranked highly with me due to her design and initial problems... but her development sorta dies out for the rest of the game. 30 / 100
Mitsuru Kirijo - I like Mitsuru, she has a good chunk of inner conflict in Persona 3... but none of it felt too memorable to me. I think I'd say she's very good in story segments but her social link isn't really relatable... almost really boring. 35 / 100
Aigis (android) - Aigis is a strong force for the story of Persona 3... plus she's a robot, everyone loves robots. Her characterization is also top notch as the game follows her slow development of human thoughts and feelings... but her robotic nature is boring at the start -\(=/)/- . 45 / 100
Naoto Shirogane - I think a large reason why I like Naoto is her voice actor in P4 and P4Golden... it's great and no one really knows who it is. However, even though she is also a great character she shows up pretty late and thus has less time to develop. 50 / 100
Chie Satonaka - Chie is a great character as she has something a lot of the P4 characters tend leave behind... common sense. She's not necessarily smart but she has the ability to put two and two together and actually contribute to solving the murders. 55 / 100
Labrys (android) - Labrys is probably the only character who has an important storyline in Persona 4 Arena, which makes sense as the whole thing is basically about her. Anyways, Labrys has great development and a tragic past
- Spoiler:
killing her "sisters"
that puts her near the top of my list. 60 / 100
Adachi Tohru - I'm not going to talk much about this character since spoilers.... but yeah he's awesome in a different way. 65 / 100
Kanji Tatsumi - Kanji probably has the most interesting problems of the Persona 4 characters and his original VA is Troy Baker; if you don't know why that's awesome then die. Also, Kanji has some of the best dialogue in the game and is genuinely a funny guy. 70 / 100
Yosuke Hanamura - Yosuke is a bit of an asshole, but I still found him loveable in the end. He's stupid, ignorant and annoying but I can't make myself hate him due to his undying friendship with the player... dude's pretty damn awesome, right partner? 75 / 100
Nanako Dojima - YOU
DON'T HATE NANAKO! 85 / 100
Yu Narukami (P4MC) - In media outside of the original P4, Yu was Atlus' first attempt to characterize a silent protagonist... and to be honest it hasn't always been good (see: Mary Sue). However, the dialogue choices in P4 and P4G that the player makes are pretty much always great and even when he's silent you can tell he's a pretty funny guy, almost a troll. 95 / 100
Rise Kujikawa - Rise is one of the first characters you see in Persona 4... in a bikini advertising some shitty drink. To be honest I didn't like her too much when she first joined the party, or even for my whole first playthrough. However, hearing her cheer you on in battle sorta grows on you over time and she does have a complex personality despite her attempts to hide it. As a side note her social link is one of the most peculiar to me as it sorta ends off where it began; she develops to see that there was nothing wrong with how she was before, just that it's not the only part of her. 84 / 100 or 100 / 100 or 84 Certified
TL;DR: I like all these characters and little thought went into the actually scores.
Also haven't played enough of P2 to judge the characters fully but Maya is pretty sleek.