The X-Men story Utopia (nominally a crossover with Dark Avengers, but make no mistake, this is an X-Men story) is problematic both within the larger context of the X-Men books and on its own terms. In the bigger picture, this story was published all of a year after the X-Men relocated their headquarters to San Francisco -- an event that was marketed as a big deal, a major change in the status quo -- so to have another big change in the status quo arrive so quickly is somewhat disappointing. Further, the line-up of X-books as a whole is suffering from "event fatigue": Utopia follows hot on the heels of the X-crossover Messiah War, and is immediately followed by the X-Necrosha event, which itself is immediately succeeded by the "Second Coming" crossover. The Events are coming so quickly that the stories and characters barely have time to breathe, and even when they do it feels like it's just treading water between events. The line seriously needs to calm down and remember that not every story has to be a Major Event.
As for the Utopia story itself, all six issues are penned by Matt Fraction, one of Marvel's bright young stars. Fraction is at his best focusing on fewer characters. Even his earlier team book, The Order, was structured so that each issue focused on a specific team member. Here, however, he's playing with a cast of hundreds, including three teams, one of which is divided into multiple squads; all these characters are being twined through multiple plot threads, and the overall impression is that Fraction has bitten off a bit more than he can chew. The plot moves along rapidly, but there's so much going on that there's very little narrative momentum to keep the reader engaged, so it's just things happening in sequence instead of an exciting story. And with so many characters all crammed into so many conflicts, very few of them have much of a chance to shine. And Fraction doesn't seem to have a grasp of several of these characters, particularly Daken (Dark Wolverine). As for the art, the cartoony style of the Dodsons and Luke Ross doesn't work terribly well with the tone of the story, especially contrasted with the sharper pencils of Marc Silvestri and Mike Deodato in the bookend chapters. This is a story that would have benefited quite a bit from a more consistent, less cartoony artistic vision.
The story is packaged nicely in an attractive hardcover edition with plenty of material supplementing the disappointing main story. Also included is the "Dark X-Men: The Confession" one-shot by Craig Kyle and Chris Yost, in which Cyclops and Emma Frost let each other in on their secrets, providing some vital background information for the main story; the superior two-issue X-Men Legacy tie-in "Suppressing Fire" in which Mike Carey, the best X-writer these days, takes his little team of Rogue, Gambit and Danger through the beginning of the conflict in the main story; the Emma Frost and Namor stories from the "Dark Reign: The Cabal" one-shot, which provide some insight into these characters; and the three-issue anthology title "Dark X-Men: The Beginning", which is basically a bunch of gathering the team stories showing how Norman Osborn assembled his Dark X-Men. These stories are not bad but are largely forgettable, serving to introduce the members of a team that got virtually no introduction in the main event; the best stories of the bunch are, unsurprisingly, those penned by Paul Cornell and Jason Aaron.
To sum up, Marvel has done a very nice job of packaging a disappointing event story with all the supplemental stories that help to flesh it out a bit. If you follow the X-Men comics, this is one you probably shouldn't skip, but don't expect to be blown away, either; the pretty cover and the hype promise much more intensity than the story actually delivers.
Continuity note: The main story in this book follows Uncanny X-Men: Sisterhood and is followed by X-Men: Nation X.