I rated this four stars, but I'd say it's really more like three and half. What I'd like to mention first is that overall I think the previous Star Ocean: Till the End of Time did better with nearly everything.
So, let's start with the good stuff. Graphics are pretty awesome, and the characters are nicely detailed, though I did find the character designs (clothing etc) a little weird. The main characters are supposed to be from future Earth, and yet their clothing looks like from your average Final Fantasy world. I couldn't really relate to that world. Overall there are some nice designs in the mix though. The only thing that looked rather crappy were some of the non-cg space battle cutscenes.
Music is fine. The usual Motoi Sakuraba fare, though I think the overall soundtrack was slightly better and more emotional in the previous Star Ocean.
Battles are fairly interesting as they are, but there's just simply too much of it. You could go an hour or two through a dungeon to get to the next savepoint, constantly doing 20-50 second long battles along the way. You can avoid enemy encounters if you want to, but you'll just miss on EXP, items and Monster Jewel bonuses (kill enough of each type and you can add bonus effects to an equippable jewel). Some areas are not accessible again once you finish them. I can think of at least two such areas. In addition to normal EXP and loot, you can increase bonuses to each by satisfying certain conditions in battle. There's also a feature called Blindsides, which is basically a move that allows surprising an enemy from behind, immobilizing them for a few seconds. Looks nice, but the novelty fades soon.
Voice acting is definitely a mixed bag. Not quite as horrible as the ones in Star Ocean 3 (like Farleen, ugh...). Voices are rather fitting, but the acting varies from decent to emotionless, even when the character's face is clearly showing otherwise.
Battles now have four characters battling at once, which makes the action ever more hectic. Keeping an eye on party members' health is basically only possible by looking at the HP numbers, unlike in Star Ocean 3, where things were more compact and you could simply see when someone is taking damage. Now the battlefields are bigger, and you can't have everyone on the screen at once. Not a biggie, but I'd rather look at characters than numbers. Another thing that's slightly broken is the targeting system. The tutorial says that you always target the nearest enemy when you attack. This is false. If you hit an enemy, and run to another, then press attack, it's almost guaranteed that you'll still attack the previous enemy. The target switches only after a few seconds. Considering the fast pace of the battle, those few seconds are worth a ton of damage you could've dealt, had you had the correct enemy targeted. Fairly annoying.
The story starts really interesting, but falls flat as a pancake once you're a couple of hours to the game. Once things start getting interesting again, the game ends. That's not to say this is a short one. Took me about 50 hours to finish, with good bunch of sidequests done along the way. There aren't nearly as many locations as in Star Ocean 3, and the variety isn't too great either. Interesting places are substituted with even more battles. Sidequests are usually fetching things or even more battles.
Item creation is much more straightforward compared to Star Ocean 3, and you can easily invent and create majority of the items during a normal playthrough.
Oh, right, and you have switch disc to visit some old locations on other planets. Like fetching items or doing a sidequest. Sigh...
Overall, a decent JRPG, but offers very little new compared to Star Ocean 3.