A fine portable adventure game, and as licensed movie games go, it's downright remarkable. The game is on the easy side, but it's good fun even for advanced players; they'll just blow through it more quickly, that's all.
While the GBA title pushes the system and gives players a truly impressive one-player package mixed with a few multiplayer elements, the DS version only adds to the previous game with duel mode and a few mini-games.
With overly long levels, it's built for road trips, but will quickly become played out within a few days. If you have to buy a Harry Potter game for the road, consider getting the DS rendition of Goblet of Fire.
Most companies believe slapping a license is work enough, and while the Goblet of Fire isn't a terrible adventure, it's not nearly as compelling from a visual or gameplay standpoint than what you could pick up for your GameCube.