Well, this is a bit of a shame. Its OK and a bit of fun but could have been a lot better.
Firstly, the duelling is great. In fact, I would give it 5/5. But the rest of the game is not as much fun. The activities are very similar (brewing potions begins to get annoying after you've done a few). A lot of the time you just watch cut scenes as the story unfolds and then you are told exactly what to do and when. They are clubs you can join but you seem to spend most of the time following other people. Hardly captures the character of Harry does it?
The graphics are very good and it has a polished if slightly rushed feel. I think a little more time could have gone into the storyline side - give Harry more freedom and choice.
Overall, not a disaster. Great bit of fun, but over priced I think. Try to spend less that £20 and you might enjoy it.