Jesus of Nazareth II was written by the Pope, so a certain, very high, level of quality can be taken as a given. I'm going to review it, therefore, in comparison to the writing of Benedict's predecessor, John Paul II.
The first comparison is favourable. There is no learning curve involved in getting to the point where you can understand Benedict's prose. It's not dense, or meandering, the referrents are consistently clear, and any reasonably literate layman should be able to approach this text and glean the meanings from it without first doing a crash course in the philosophy of Kant and Scheler. No one will have to set up an institute or start producing booklets and pamphlets to explain to the faithful what on earth he's talking about. Stylistically, this book preserves everything that is best in the German temperment: it is clear, sane, restrained, tidy, and generous but devoid of excess. Good.
The second comparison is less favourable. Although absolutely orthodox, extremely clear, highly edifying, and chock full of sound teaching, this book is short on jeweled insights. It does not flow over with bubbling streams of the wine of the spirit the way that Theology of the Body does. The experience of reading it is distinctly lacking in goosebumps and chills. It does not kindle the desire to jump up and down and sing wild hymns about Goodness, Beauty and Truth. You don't feel the entire panorama of human life opening before you like the first of the spring flowers. It's more like taking a hike along a pleasant but familiar path than like climbing up a difficult and often onerous mountain punctuated by sublime and dizzying views of the cosmos. Now I'm sure that that's good for someone like me: occasionally, it's helpful to be grounded. I'm equally sure that this will appeal massively to the majority of Catholic readers, most of whom seem to prefer to walk on the safe side of the road. I think it less likely that it will inspire a lot of people outside of the fold – but I'm not sure that it's intended to do so.
The content is fairly straight-forward: the second half of the life of Jesus. It's a good if somewhat academic portrait, and its primary purpose seems to be to clear away a lot of the flotsam that has accrued around the person of Christ in the course of the modern age. Most of the errors that it corrects for are the sort of theories that biblical scholars and theologians seem really prone to, but that anyone with a well-developed sense of taste will discard immediately simply on the basis that they have no aesthetic proportion whatsoever. Theories like the idea that there's a fundamental discontinuity between Jesus' early ministry and His later ministry, or that expiation is contary to forgiveness. Benedict does a good job of sweeping such notions aside and revealing again the traditional figure of Jesus, a clear, recognizable, and convincing Jesus, the one that we meet in the gospels, the one that changed the world.