08's self-description as a "graphic diary" is to let the reader know what he'll get is not a comic book-style retelling of the campaign, but an illustrated, slide-show style recap of the campaign, with occasional commentary by two fictional beat reporters.
On those merits, the book is great for those who were on the blogs every minute; every twist and turn is recounted in beautiful black and white pop art. Nothing new will be revealed by the book, but it has a very entertaining nostalgia factor.
One criticism, however, is that about halfway through, the narrative stops explaining things. Someone new to the campaign, or ten years from now, will have trouble understanding the context or the figures (e.g., Gov. Bill Richardson does not get a caption despite being drawn in such a way that his beard makes him look fundamentally different from his primary race depiction; also, no caption for Sen. Edward Kennedy, who while famous to policy wonks, is not that recognizable). The implosion of the Clinton campaign, which was the subject of a fascinating review in The Atlantic, is reduced to cable television-worthy sound bites; similarly, Joe the Plumber is reduced to his celebrity and not the arguments over fiscal policy that dominated the last month of the campaign.
I would recommend this product to anyone who has the Shepard Fairey Obama poster; it's got a similar iconic and sentimental value, and is definitely worth it for those reasons.