I'm enjoying it (even though it's shounen, it seems a little more seinen to me). The character designs are definitely Kubo ( that distinctive style) and she's a good story-teller. Certainly worth reading (a review is on the way).
Just finished chapter 1 of volume 1 which I'm guessing equates to one (of 7) volume(s) of the original release. It finishes with Nausicaä and Asbel escaping the floor of the forest that they discover is clean. Whilst mainly the same as the film a number of plot points are different such as instead of the embryo of a giant the Pejite princess is carrying a stone which essentially appears to be a key to controlling the giant which is still in Pejite. Also Nausicaä isn't a prisoner of Kushana, but under her command due to an old treaty and they're on their way to attack another country when attacked by Asbel. Another slight change is that in the film it is implied that Nausicaä has an affinity with nature whereas the manga says it right out with her hearing what the Ohmu says and even telepathically talking to Asbel. I'm liking it so far in that it is similar enough to the film that I enjoy it, but different enough that I'm getting something new. As it's already a long way through the films plot I'm guessing there's going to be plenty of new stuff to get into.
Nausicaä of the Valley of the Wind Vol. 2
The bits that appear in the film are done by about half way through this volume. The differences being no appearance of the giant yet and the prophecy about Nausicaä being delivered by a different person. So into new territory and everything seems to be on a grander scale, but with that it's a little confusing with more peoples being drawn in to it than the film.