I just came into possession of KH: BBS, myself. I've avoided all spoilers, but given that the three mains are nowhere else to be seen in the continuity, I've already figured I'm going to watch meet their untimely fates on at a time.
The controls are okay, the voice acting is somewhat hit and miss (seriously, Terra and Ven sound just fine, what happened with Aqua's voice VA, was she on valium?), and following three individual paths is interesting though been done before. I'm just happy to see a new KH game altogether.