I liked the missions, and the gameplay, I found it rather fun, despite the repetitiveness. And you do get to experience playing as different Organization members, so that's a plus. There's also some AkuRoku friendship build up that was needed.
Otherwise, I could have done without the game. Everything else sucked. Xion's basically the plot, and that doesn't even start until Day 200 something and straight at the end for that reason. Also, don't expect a lot of Organization XIII, or whatever you might think you're getting out of them: back story, more depth. Nope. It's basically the RAX filler junction.