It's a hit or miss sort of thing.
The most important thing to remember when considering this game: it's NOT a Pokemon game. It's basically an improved rouguelike with Pokemon in it. (a.k.a The 'Mystery Dungeon' series = easier rouguelike with an actual story, music, and better graphics.) If you want a good idea of what the gameplay is like, go search Google for 'Nethack' or 'Crawl', play a floor or two, and decide if you like the gameplay or not (don't worry, Mystery Dungeon is much easier). Play through a few characters. If you do, buy it. If you do not, don't. Younger kids might not have enough patience to sit through a proper dungeon, but the game's major messages (take pride in what you do, don't ever give up, always help others, and learn to have gratitude) are worth it. Oh... the game is playable without knowing how to read, but it sort of looses all its purpose and charm, so only give it to READING kids.