I've adopted this book for a class I teach in digital systems design. I agree with another reviewer that the book has problems for instructional use. It does overwhelm the student in the first chapters! I reduced the problem by writing a VHDL introduction I give the students, and telling them to only skim sections of the first few chapters of the book.
I'd also warn against assigning problems from the text. I've found that the frequently require knowledge gained only after reading latter chapters or require VHDL features that are missing from the software that we use.
I know this sounds like a negative review, and you might ask why I gave it 4 stars. Where it wins is in that it is very thorough and isn't a "throwaway" textbook. It's the closest book to reality that I've seen. It's also very well priced.