Read this book because it is the text for our PhD Econometrics I course, also mainly because it is recommended by Professor D, so first comes his comments on the book.
"The standard PhD level first text on Math. Stats in all serious stats and econ departments."
Serious yes, from a point of view of a statistician, so really gives you a very good structure of the subject.
Personally, believe that chapters before regression is really well written. The regression part may be too concise, OK, after all, that may be the task of a econometrics text. But I still believe that if the authors could explain the later chapters using matrix is would be more elegant and intuitive.
I did not do the exercise and have a very weak stat background, which makes me rather difficult to follow the serious proofs and logics in later chapters.
I would read it again very soon and do the exercises at the same time. Hope it would be better.
After all, it is a very standard grad stat book for econ students. Harvard or MIT also use this one for their students at that level.