If you need one book on XML that covers a large proportion of current XML applications, then this book would get my vote.
On the whole the book has both breadth and sufficient depth, the authors all know their subject areas and always point you to where to get more depth.
The CD has a nice interface (auto-starts on the PC without installing any fancy viewers) and includes a good HTML based interface for cross platform access.
I can only make two minor criticisms:
1) Missing from the CD is a complete list of web links given in the book, so you have to type them in manually.
2) There are several large tables that cover several pages! Personally I'd prefer them to be available on the CD (there is only 440Mbytes used) in XML of course.
If you need one book on XML that covers a large proportion of current XML applications, then this book would get my vote. Recommended.