I've owned this book for years and would say that the reproductions are excellent. The colour plates are on good quality paper and provide a high level of detail, with a satin finish. Having seen some of Freud's early paintings recently at a small exhibition in London, would say the tone and colour matching is about as good as is possible.
Although this book is not a comprehensive monograph capturing Freud's entire output, it still makes for a solid reference illustrating how Freud's technique has evolved over the years, starting with the highly wrought early portraits moving onto his more expansive oil paintings executed in hog bristle.
I find it particularly good at illustrating the very fine detail of the head paintings from the 1950s.
There are 99 colour reproductions ranging from 1947 to 1987 with the emphasis firmly on studio figurative work.
What's missing: a lack of illustrations of drawings and etchings. And as another reviewer has noted, there is not much text by Robert Hughes to accompany the pictures. So if you are interested in the life and times of Freud, then you'll need to look elsewhere. But of the text there is, it is well written and informative.
If you don't want to commit just yet to spending on an expensive all-in-one monograph, and you're interested more in the paintings than the drawings and etchings, then I recommend starting with this book.