Just watched the Disappearance of Haruhi Suzumiya movie at Tokyo Shinjuku Wald9 yesterday.
It was awesome. It's a long movie (2h42m) but i'd dare say it's totally worth it, and the quality of the movie is totally worth watching in a theater.
I'm not a deep fan of Haruhi series so I only know about the TV and DVD anime series (haven't read any of those light novels) but this disappearance story is probably the best for filming. It's somewhat related to most of the scenes you're familiar with and explains some missing pieces (but adds more as well) from "Sasanoha Rhapsody".
There were some scenes that actually made me cry. I'll give it 9.5 stars out of 10, which is probably the highest rank for an anime movie i've ever seen -- as good as "The girl who leapt through time".
There were two british girls next to me watching the movie and after the movie I talked to them; they apparently enjoyed the movie i.e. the quality of moving pictures but without a proper Japanese skill it's hard for them to grasp this complex story.
It might take some time before it gets a non-JP release with subs but I totally recommend this if you enjoyed the first season and the Sasanoha Rhapsody episode. (All other eps from season 2 are just crap - you can ignore them :))