There are many high points in this game that you will remeber long after it's other basic characteristics are forgotten.
The best usage of Disney could be the colorful movie-inspired worlds and the unforgettable cast of characters that can fight along with you. You will move from world to world excited to see the next familiar area to explore. The voice-overs for the Disney characters are surprisingly good with only a few moments of "Did that just come out of their mouth?" thrown in. The Final Fantasy voice-overs, on the other hand, are pretty awful. Only "Leon's" ( you know him as Squall) voice seems to fit him well. Actually overall, the Square feel seems to be lacking with horribly easy combat (button mashing anyone?) and original characters resulting in headaches from annoying dialogue and cheesy actions.
Any rpg/Disney fan will surely come away pleased after finishing Kingdom Hearts. With a drawing story, fun feel, and great Disney cast, this not-soon-forgotten game tends to set a high standard in the PS2 world, which is no small feat.