If you can get past the dull plot and recycled gameplay formula, then you may find a lot to enjoy.
However, to Birth by Sleep's credit, the gameplay formula is a very enjoyable one. The graphics are beautiful, and the controls, while somewhat uncomfortable to use, work well. It's also nice to play as Terra, who struggles with his inner darkness, and Aqua, who tries to understand the relationship between light and darkness, instead of always playing as Sora and Sora clones like in most Kingdom Hearts games.
In conclusion, if you can get past Birth by Sleep's unoriginal plot and similarities to past Kingdom Hearts games, you may find the gameplay enjoyable and the game's new twists on Kingdom Hearts protagonists to be a welcome experience.