Well, the only Star Ocean I played was the original one, released by the SNES and I must say that I was really impressed by it! It was one of the few games (if not the only one) for Snes that featured voices. Granted, only the introduction of the game featured voices but meh, it still was impressive, at least for a SNES game.
The story was kinda weird but quite enjoyable and I sure loved the whole affection system. It basically consisted of 'getting close' to someone. Every time you went inside a city your party would disband and would let you alone to roam free through the city and, when you were ready to head out, your party would follow you. The good thing about all this is that you could interact with you party members inside the city and that way you could 'get close' to them.
Now, the whole buddy system really shined during combat. If your 'buddy' fell during battle, the main character would enter into a berserk-like mode gaining incredible strenght. Can't remember much of that berserk bonus since it's been a while since I last played it.
I liked the combat system a lot. I think it was completely different from the static battles that were quite popular in the Snes. Instead, you got to move around the map as you battled. Well, it was more like, every time you clicked to attack an enemy the character would move near that enemy, attack and stay right on that place.
I also liked the fact that you got to recruit
LOTS of characters. Can't really tell you how many there were but there were lots of them! And there were times that if you choose to recruit someone, youu wouldn't be able to recruit another character.
Well, overall, I sure did enjoy that game. It was on the top of my favorite games for hte Snes, along with Chrono Trigger and Final Fantasy VI. If you haven't played it, you should! Or just wait for the PSP released of that game, since it seems SE is porting that game for the PSP! Yay
(Though I'd love to see some improved graphics >.<)