I have seen the first episode for free on the Marvel Website from memory, or perhaps a trailer of it. It's a fantastic adaptation of the comic books, with good voice acting music and stylish motion picture animations true to the comics.
If you haven't read Astonishing X-men I would highly recommend it as it's a fantastic read, and the motion comics are amazing adaptations of the material. To be completely frank, for the price I was half-expecting to find myself with the first episode or two, at least one of which is readily available online. For anyone who is unsure, I recommend checking out the trailer or episode one to ensure they are happy with the style. I personally loved it. My only complaint about the Bluray is that each ‘chapter’ isn't split up into different episodes, but rather a long movie, yet still cuts in and out of credits at the end and start of every chapter. Making navigation more difficult than it should be in my opinion.