To open with the positive, the movie itself is fantastic. I'm a huge Harry Potter fan, but have been very critical of the adaptations so far. Half Blood Prince is my favourite book and I was very happy with the way the film kept the most important elements. Special note should go to Alan Rickman for, as ever, a brilliant performance as Snape and the ability to say so much with a simple look.
Now for the negative. The so- called 'digital copy'. The leaflet inside claims it's compatible with Mac OS X and iTunes. But no. Apparently it will ONLY work with Windows and Windows Media Player. I have read and reread the leaflet, and got my partner, who is a lawyer to reread it, and it clearly states that it is compatible with my system. It's only when you get onto the website that you find it doesn't work. Also, I didn't find a way to contact the site in order to complain.
So, worth getting for the Blu Ray/DVD copies, but don't put too much stock in the Digital one if you were hoping to use it on any iPod or similar.