Packaged in a paper sleeve, Threats of the Nentir Vale includes a 129-page soft-cover book that abides by traditional dimensions of Monster Manuals past, eight sheets of monster tokens, and a poster map that gets referenced in some of the monster entries. Unlike other monster supplements, this book provides regional content for the Nentir Vale and only features monsters in the Heroic and Paragon range (the highest level monster is 20). While the actual book is the proverbial meat of the product, it seems a bit on the thin side: there are only 40 separate entries (Monster Manual 3 had what, over a hundred at least?), with a good mix of monsters and villainous factions with tenuous roots in the Nentir Vale.
In terms of presentation I'm very pleased with the book in spite of the recycled artwork--cadaver collector, mooncalf, and ragewind come to mind, and each monster has several paragraphs of flavor content to give you a foundation for what the monster is about and spark your imagination with adventure ideas. This book is very useful if you plan on running games in the Nentir Vale, but (perhaps) aside from names nothing is stopping you from porting these organizations or locations to, well, anywhere else. For example the Barrowhaunts are a band of undead adventurers that haunt the Sword Downs. You could very easily file off the names and use them for any level 9ish encounter in which undead are warranted.
Portability aside, a lot of the organizations help round out existing monster entries like hobgoblins, orcs, dragonborn, tieflings, and even felldrakes. There are some new monsters, however, by which I mean almost entirely monsters from past editions making a belated return, such as--again--the cadaver collector, mooncalf, and ragewind. Seriously though, there's also boggles, a werespider nestled in the Hunter Spider faction, penanggalan, liondrake stationed in the Dythan's Legion entry, peryton, big-ass mimics, and more.
Despite the Nentir Vale subtitle, this book should prove to be almost as useful as any other Monster Manual on your shelf. As I've emphasized several times, they are easy to modify and displace assuming you want to keep most of the flavor attached. Even if you detest the implied setting and all that it implies, there's a good chunk of monsters to round out the existing stock along with new additions. The only downside is the price tag, as $30 formerly got you a hardcover book with almost a hundred extra pages. If you like tokens then it definitely makes it worthwhile. Otherwise, not so much.