I'm Chris' friend, I'm the one that normally pushes a majority of the mechanics out onto the paper, since I tend to be pretty good with coming up with simple, yet deep Role Playing Systems. The Persona RPG and Breach are both ran off of a similar ruleset, but with drastic variations in which they are both used. They both split up the PC from their Persona / Anomaly, with the PC having the social stats, and the other dealing with the combat statistics.
The Persona RPG draws heavily from the way the game Persona 4 was played out, in the sense that there are five different social stats; Courage, Knowledge, Diligence, Expression, and Understanding. Social interaction is VERY free form, in the sense that if one were to get into a fist fight with another student, they would explain how they were attacking to make it more cinematic, while rolling successive Courage Vs. Diligence rolls until the Game Master decided it was drawn to a conclusion. The social stats also level up on their own, each stat having its own leveling curve, lending to the fact that in real life, the more you interact with people in a certain way, the better you become at interacting in that manner. The Persona's stats are broken up into five blocks as well, Strength, Magic, Energy, Agility, and Luck. When generating your Persona, you choose a good stat (That is a d12.) and a bad stat (Which is a d4), while the rest are left at a d8. One would also choose one elemental strength, and one elemental weakness to start off with, though with the Tarot Card and Social Link systems, those can adjust later (As can stat blocks.) Personas level up via general RPG fare, with EXP and things of the like. The Roleplaying aspects can be anything one could imagine. It's a very open system.
Breach, on the other hand, is lighter when it comes to rules for PC's, ranging the stats down to Vitality, Mind, and Skill (With Skills being Physical, Mental, and Presence, respectively. There is also another skill that comes from your character's Job, which also ascertains what kinds of Anomalies he or she specializes in working with.) In stark contrast, is the extensive list of Anomaly types that can be mixed and matched to create one's Anomaly. Some types grant bonuses to certain stats, while providing a detriment to others. (The five stats for your Monsters are Power, Vitality, Mind, Agility, and Affinity).
If there's anything any one wants to know in specific, I'd be happy to elaborate.