This book is the best book currently available about SAP BI reporting. That said, other books on this topic (mainly by Norbert Egger) aren't particularly convincing. So there isn't much competition. Besides as another reviewer mentioned, it is much cheaper.
Peter Jones explains the concepts well and in greater detail then you will find elsewhere. There are lots of useful examples, tips and tricks.
This book devotes a lot of space to the query designer - this is the central tool for all SAP BI reporting - and covers it well. It has another two chapters on the report designer, a module that SAP is going to let die, so one might consider this bit a waste of space. The information broadcaster is also covered quite well and in sufficient detail.
Peter Jones decided to add a chapter for web reporting and the enterprise portal plus half a chapter each for the visual composer and integrated planning. I suspect he did this mainly, so he could say that he had covered all the front end tools.
Unfortunately the lack of space means these topics get short shrift, as you could easily fill a complete separate book for each of them. The VC and IP bits don't tell you much more than that these modules exist and why they might be interesting.
PJ has announced a book covering web reporting and as the Web Application Designer won't be replaced before 2013 (Business Objects Pioneer in the SDK version), I am definitely going to buy it.