After hours and hours waiting for it download and then a bit of tweaking to get the 1080p to run somewhat acceptably on my crappy computer I finally watched The Disappearance of Haruhi Suzimiya and it was quite simply incredible. Not only was the animation so much better (understandable since it was a film) but the story was top-notch and they even managed to develop the characters further after two series. I grew towards Yuki much more than I had previously, especially her alternate self, and couldn't help but love Haruhi throughout as her typical self (with her behaviour at the beginning making me think even more that she resembles K-ON!!'s Ritsu).
Despite it's 163 minute running time not once was I bored and willing it to end and when it finally did end I was actually a bit disappointed there wasn't more, I'd have been more than happy to spend the whole day watching. The pacing is perfect, with revelations around every corner yet still remaining easy to follow.
I'm aware that I'm not exactly the best reviewer ever but the main impression I want you to get from this post is: Watch It! If you've watched the series - watch this film, if you haven't watched the series - watch the series then watch this film. You will NOT regret it. It'll be a long time before I watch something that tops this.