Gameplay
The gameplay uses a turned based JRPG battle system, but contains a twist common with the Shin Megami Tensei series; the turn press system, which gives you another chance to attack if you find the enemy's weakness. As you progress through the game, you're able to fuse/gain more Personas to fight enemies that will get stronger. There are also bosses in Tartarus, which can be difficult to battle. Very difficult. Some don't have weaknesses, and you'll have to rely your luck to get critical hits. When all of the shadows are weakened, you're able to do an All Out Attack, a skill where everyone in your party attacks all enemies at once. The gameplay does have flaws however, such as how you're only able to control the protagonist during battles, instead of the entire party. This can lead to party members not doing what you want them to do, and can sometimes make you fail in battle. Another gameplay flaw is the fatigue system. Staying in Tartarus for too long can make characters tired, which will make them not preform as well in battle.
The story in Persona 3 is, in my opinion, one of the greatest stories of all time. It's not easy to talk about without mentioning spoilers. The characters are also well written too. They feel the most realistic in the series, as you can tell that at times they don't want to work together, but are forced to. The story pulls many twists with events and characters.