Movie Trailer: How I Live Now (2013)

I had heard they were planning on making a film out of Meg Rosoff's How I Live Now but I somehow missed all the casting news and production details until the trailer came out (as usual). Anyway, it's been awhile since I read the book but it looks like it's remaining pretty close to the text and Saoirse Ronan is always a good casting choice so it could be a decent little YA film.

Has anyone else read the book? I remember not loving the narration (first person, no punctuation, occasional txt speak) so maybe making it a film will actually improve it!