It has been out on the X-Box for ages, but the PS3 is better because it has the Japanese soundtrack/English subs so you're spared from the horrible voice acting
I think it also has more content? I think I'll wait until this goes down in price before I get it, I loved Star Ocean: The Second Story (PS1), but really didn't like Star Ocean: Till The End Of Time towards the end of the game even though the vast majority of it was good. So am a little concerned about how good Last Hope is (or isn't).