Three stars for a book that has a number of positives and negatives.
First, the positives! The illustrations, as many have said, are quite beautiful. Be aware that they follow the concept art style of Dragon Age 2 and subsequent material (Silent Grove, etc) more than Dragon Age: Origins. Not unexpected, as that seems to be the overall art direction of the franchise. A little more vibrant, a little more stylized, but you lose that edge of realism if it's what you prefer. Either way, it's a personal preference issue, and the art in the book is plentiful, high quality, and much of it is brand new. The layout is excellent, reminiscent of a textbook with main sections and plentiful sidebars, the latter of which range from more detailed analysis of a topic briefly touched on in the main body of the text to humorous anecdotes, timelines, and more. While the layout is 'textbook,' the author's have done a good job of making sure the text itself never lingers on one topic long enough to become dry - this is intended as an entertaining reference to a fictional world, and it pulls that off nicely.
Unfortunately, there are negatives, as well. One is not rightly attributed to this book alone - canon issues within the greater Dragon Age universe. They are numerous at this point, and there is nothing this book could have done about them within it's pages, though it does introduce some inconsistencies that are all its own, as well, which have already been pointed out in other reviews. Be aware however that the information here should be taken with a grain of salt, especially if being used as a reference for a tabletop campaign, fan fiction, etc. Hopefully Bioware can sort out the canon issues and provide a definitive version; it would have been nice if something like that could have been done before releasing a reference guide, or perhaps they intend for the information here to be considered definitive. Also, very little of the information contained here is new, or even provides new details on old information. Careful reading of codex entries in DA:O / DA2 will give you most of the information in this book. For a new retail product, it's not entirely unfair to expect the author's might add further elucidation of important detail, or entirely new information, rather than just gathering what's already known.
While general canon issues within the universe reach beyond the scope of this single work and can't be held too much against it, the build quality certainly can. I've seen a few reviews say it has "excellent binding" or is "sturdy." Neither is true. The book uses a wax-chord binding - one of the cheaper binding methods available and one which results in your pages becoming loose due to the perforating effect if the book is referenced often. It also means that if laid open, the page edges will not line up, creasing some portions of the binding more than others. The pages are high gauge, quality paper, at least. The cover is decent but a bit flimsy, made of a fairly pliable cardboard. Overall, nowhere near the construction quality I would expect of a book retailing at 39.99 MSRP - it reminds me of those oversized coffee-table children's books more than anything.
Is it worth the money? Probably, to a die-hard Dragon Age fan, who are most likely the only people reading this anyhow. Just know that you might already know everything here, and that it probably won't stand up to constant use as a reference for a tabletop campaign or something of the sort. It's fun to read, though, and would like nice as a coffee-table piece in a collection.