Problem with this book is it is a bit woolly and wordy. However, the main difficulty is there simply is no other book around on the market. As a description of the entire end-to-end ETL process, including many subject areas I'd not even considered (eg. COBOL copy books), it's very good.
However, I'd say the REAL reason for buying this book is it works well with Ralph Kimball’s other work "The Data Warehouse Toolkit", and gives an excellent summary of Dimensional Design. I guess the authors felt they must put this in to explain the background. Personally I found it invaluable.
Also the description of "real time ETL" was invaluable. Everyone's talking about it, but the book gives a credible outline solution.
Yes woolly, yes it uses 10 words when two would do, but overall I got a lot out of it.