I have read it and found it very helpful. Obviously you would need to be experienced with Empower to gain some benefit. The author starts by saying that so many calculations in labs around the world still rely on invalidated software packages like Excel to do their calculations and reports when its all at your fingertips in Empower. Of course most labs are too busy to invest in deeper knowledge of software...
Its split into 9 topics- Background and Networks, Quickstart, the Project Window, Acquiring Data, Process of Data, Reports, Data Import/Export, Custom fields and COnfiguration Manager.
For me personally I thought this was an excellent guide that outlined the intermediate and advanced features of EMpower 3. I learned so much from the Configuration Manager section which explains all the audit trails, user groups and setting, cloning projects etc. The weakest chapter was custom fields, little more than a very basic outline but then again they offer a separate book about Custom Fields which I also have and rate highly. The chapter on reports is also very good and explains a lot that experienced users may not be aware of.
I would recommend it.