The existence of a Ghoul supplement for Vampire: The Requiem was inevitable. Unfortunately, what we were given ended up being more than a little disappointing.
The book's main pitfalls are that it doesn't tell us a whole lot more other than what we didn't already know, and that it skimps out on a lot of vital information. Where the book shines is the truly original material, although it doesn't feel like there was enough of it.
To begin with the plusses, the book introduces some interesting new concepts. One unique introduction is mandragora, which are ghouled plants. The book goes into great detail as to how mandragora are created, their uses, and what sort of plants are able to survive and flourish under the ghouling process. Added to this is the introduction of lacrima, aka Mandrake's Tears, which is a sap these mandragora can produce. The sap is poisonous to humans, but potentially addicting to Kindred, and sometimes crafted into a kind of rare wine. It is easy to see the many applications of mandragora and lacrima in a chronicle, and this section can be inspiring to storytellers and players alike. The next area where the book excels is its treatment of animal ghouls. It presents many ideas, including short examples, about how and why Kindred might ghoul animals - from domestic cats to falcons. The book is an essential read for those who wish to use animal ghouls in their chronicle if they're looking for something outside of simple antagonists. Lastly, there is the introduction of ghoul families, which are similar in concept to the revenants of Vampire: The Masquerade. One of the main differences between OWoD ghouls and their NWoD counterparts is the potential for female ghouls to give birth. As such, it is possible for ghoul lineages to be created, and the book goes into great detail about the mechanics and existing ghoul families, and how to create your own. The profiles and histories of the pre-existing ghoul families are interesting reads and inspiring for those who might want to use NPCs, or have their vampire/ghoul hail from one of them.
Where the book is less than inspiring are the examples of how each clan might treat their ghouls. While it presents clear enough ideas for how ghoul/regnant relationship dynamics might play out, there is nothing really groundbreaking or truly inspiring here. A little better, and far more detailed, are the sections describing how the individual Covenants typically treat their ghouls. This section is particularly important, *particularly* if a ST or players are planning to drag their ghouls to a Covenant function.
As stated before, where the book falls flat is where it omits, glosses over, and reiterates what has already been said. Being that Masquerade is the predecessor of Requiem, and consequently some of the supplements are going to go over relatively the same material, it is only natural that some of the Requiem books are going to be held up in comparison to the ones that came before it. Where Ghouls is concerned, although it does a good job covering the new material, overall it just isn't as good a book as Ghouls: Fatal Addiction, the Masquerade supplement.
Ghouls in nWoD and oWoD aren't that different. They're both addicts, but for somewhat different reasons. Vampire vitae is physically addictive in itself in Requiem, so ghouls in Requiem are enslaved by both vitae addiction and the blood bond, whereas ghouls only have the problem with the latter (although they can, and often do, become psychologically addicted to vitae). The end result is basically the same; however, the difference here is Ghouls: Fatal Addiction does a far better job of describing what that affect is on the ghoul's life. It goes more into detail with details of ghoul existence - such as the types of sick games vampires like to play with their ghouls - where Ghouls describes it flatly with a sweeping brush, and focuses more on the fetishistic sexual power dynamics of ghoul/regnant relationships. G: FA also went into detail about the general types of ghoul categories and their attitudes about existence and being a ghoul. This is notably absent in Ghouls, which is detrimental when trying to get into the ghoul mindset. Shamefully, although the idea of rogue ghouls is mentioned, it is only barely spoken about enough to make the character. The book does not give an in depth perspective about the lives of rogue ghouls, something which was richly present in Ghouls: Fatal Addiction. This also means that canon independent ghoul groups are absent, and are basically only hinted about in the book, leaving players to create their own with an absence of examples. Another thing that is shamefully missing from Ghouls - derangements. Ghouls are strange creatures, their bodies, minds, and lives forever warped by their domitors and vitae. As such, there are a wealth of potential derangements that could affect a ghoul that are unique to them. In Ghouls, derangements get a single page, and none of them truly reflect just how messed up and unique ghouls are. In this case, I believe this is one of the sections that could have been (and should have) been directly recycled from Ghouls: Fatal Addiction, with the addition of those present in Ghouls. Lastly, intriguing story prompts that could have been recycled from the old ghoul book are absent in the new. This is a minor qualm, but it is undeniable that these ideas could be helpful to STs or players.
To sum, Ghouls is certainly a helpful book to those who want to use ghouls in a chronicle, and essential to anybody who wants to play a ghoul. However, for all of its omissions, I would also argue that to get the most out of ghouls in a chronicle, Ghouls: Fatal Addiction is also necessary - Ghouls is an inferior book. Yes, it is Masquerade and not Requiem, but ghouls in both settings aren't wildly different. It gives more ideas on how ghouls are treated in vampire society, and more insight on potential ghoul/domitor relationship dynamics, as not all vampires and ghouls are the same and aren't going to be in a Story of O-type relationship. Additionally, as Mekhet like to experiment with ghouls, the sections of Ghouls: FA in which a Malkavian doctor discusses his insights/experimentations with ghouls could be inspiring to Mekhet players to graft onto their own characters. The Revenant families in Ghouls: FA could be modified and ported over to Requiem for those who like them, or used as inspiration for those who want to make their own ghoul families. What also could be ported over or used for major inspiration are the the independent ghoul groups and the derangements, sadly missing from Ghouls. I understand that the writers did not want to retread old ground, but it is important to bear in mind that Ghouls: Fatal Addiction is an out of print book... Ghouls had big shoes to fill, and just didn't live up to the standards set by its predecessor.