In general, I was pleased with "The Encyclopedia of Angels." I became interested in angelic lore through playing a video game (the game in question was "Persona 4"), and immediately became interested in having a more thorough description of many of the angelic beings found in that game. In that sense, this book does not disappoint.
However, the book is not nearly as thorough on individual angels as, say, an internet search would be. While each entry is nice and complete, a quick google check gives me 10x the info found in this book. I know this is an unfair criticism, but it is worth noting nonetheless - if your interest is deeper, you should do more thorough research. Moreover, I was disappointed in some of her references - I don't really care about angelic references in film. But this is merely personal preference, and while I dock the review a star for this, I understand if others take me to task for it.
Nonetheless, having the information ready at hand, in a nice form, with illustrations and artwork, cannot be overlooked. All in all, I would recommend this to anyone who would like to begin to understand the vast panoply of angelic beings and lore out there. However, for a deeper study, one should go elsewhere.