The first thing I notice upon unpacking DCC is that the book is huge and heavy—almost 500 pages of thicker-than-average paper. The second thing I notice is the extraordinary quantity and high quality of old-school art. You've probably already heard that many of your favorite old (Jeff Dee, Russ Nicholson, Erol Otus, Jim Roslof) and new (Stefan Poag, Peter Mullen) old-school artists produced illustrations for DCC, but it still takes one by surprise to find large illustrations on at least every other page.
I haven't mastered the DCC rules yet, but I see a lot I like.
The character funnel, where each player starts with several zero-level characters and sees which one survives, is something I'd like to try at the start of a campaign. I'm not sure how often I would use it for the same group of players, but the funnel is robust enough to be more than a gimmick.
The spell system is different than the one in D&D. When I hear about new magic systems, I always remember and repurpose that Churchill quotation about democracy: D&D Vancian magic is the worst magic system except for all those other magic systems that have been tried from time to time. That said, DCC's magic looks like a lot of fun, and the increased magical unpredictability fits the tone of the game well.
DCC is light on stock monsters (though not so light as Lamentations of the Flame Princess). The monster section begins with advice to the referee about customizing and creating monsters. This is only one of a number of design decisions that show DCC is intended for the kind of gamers who already have a few twenty-year-old monster collections on their shelves.
And even though I'm hardly an RPG newbie, I'm not sure I'll jump into DCC as a referee. Unlike a lot of gaming material I buy only to read, I would actually like to play DCC at some point. Unfortunately, I won't have enough time in the foreseeable future to learn the game well enough to run it myself. That, I suspect, will be the pinch for DCC: the audience is experienced gamers who have enough time to learn a new system and the inclination to do so.
It would be very cool if Goodman Games themselves or enthusiasts they recruit ran regularly scheduled games at cons and online for people looking to get a feel for the game in action.
I have one or two nitpicks with the book (the line art should probably have been reproduced at 1-bit color depth to avoid "fuzziness", it's Edgar Rice Burroughs not Edward, and where the hell is C.A. Smith?), but none that seriously affects my enjoyment of the book or its utility.