This is the best in the series by far. Any fan of the first two games should give this one a try.
Ont top of all that, this game leaves the stealth aspect from the first two behind, shooting it dead. It's all about the action, the puzzles, and the boss fights. Most of these are really good. There are some truly challenging puzzles, but nothing that'll make you suck your thumb and crouch into the fetal postion. Most of the bosses are cunning and require specific attacks at specific times, making it just not your average button masher. While all of those are great, the only thing that mars this awesome game is you can't fly on a broomstick at all. Instead you fly on a Hippogriff. While you still get to fly, this replaces both of the Quiditch matches with lengthy scenes. The main reason the first two games were enjoyable was for the Quiditch.
The sound complements this game perfectly and pulls you in. The tracks are really excellent and were composed really good. Overall, I love this game to death, and would love to buy it again. If you like platformers AND excellant action/adventures, you'll more than likely love this game.