This book does wonders for the characterization of the team without sacrificing its pages to long, drawn-out, bore-inducing dialog. There's just enough going on that it keeps it from becoming a chore to read, and that's great for a set-up phase.
Each character gets a bit of description, and it brings the reader up to speed with events they may not know about. Some characters, like Doctor Strange, haven't had their own series in awhile; the opening pages of this book do a great job of setting the person's tone for the reader.
This is important because a lot of these heroes have gotten a bum rap for being incapable of carrying their own books on their back (well, except for the Hulk, arguably). Putting them together seems like a good idea, as long as they can keep the challenges threatening and the writing solid.
This book has a very light-hearted tone to it despite not having an overly-comical premise. The goal the Defenders are looking to achieve is right there and set out, and now the team has to hit a number of steps along the way. It's simple outlining, but it fast-forwards through the long start-up that a lot of Marvel books have had problems with (crossovers especially) and gets us right to the meat of things.
Issue one sets up number two quite well without resorting to hokey cliffhangers or full-page reveals; in short, it looks to be a wild ride that is rife with good storytelling. That's something we need more of.
I think the Silver Surfer's introduction was a bit short-sighted, as there's been some changes to his characters that weren't quite explained. Norrin's transformation in the pages of MIGHTY THOR don't seem to line up quite nicely with the personality that's displayed in this book, which is weird, as Matt Fraction writes both of them.
However, I'm willing to forgive that one little foible because this issue had me smiling from beginning to end. Like I mentioned above, the threat of the book doesn't leave your head scratching in confusion, the characters are well laid-out, and the consequences are apparent without having to rely on cheap stunts for shock and awe.
In short, DEFENDERS feels like a classic in the making from issue one, as the story, characters and purpose seems thought out and properly scouted. This book deserves your attention and dollars, if only to keep it from falling under the waves of drudgery and higher-selling books.