None of the examples goes in-depth enough, and the level of the book is very strangely targeted. I bought it expecting to perhaps be out of my depth since it is intended for enterprise level developers, but in fact I can't see it suiting any level of developer.
The examples are not very high level, hence unsuitable for developers, whilst the examples that are given, frustratingly, lack any kind of step by step help for beginners. Want to set up an Outlook form which has an option box for polling your customers? Rizzo says you can do it, but not how you can do it, and this kind of stuff is repeated throughout the book. As such this book is really only useful for evaluating Outlook rather than using it - it is very useful to have by your side when presenting Outlook/Exchange to your company as a possible new mail client/server solution, but for anything more 'advanced', even basic form design, you are going to need something with more meat to it, like Mosher's book on Outlook programming.
To be honest, this book is really just PR for Outlook and Exchange, and could have been written by anyone who has surfed the Outlook and Exchange sites for a few weeks and looked at the Outlook and Exchange programs for a few hours.
Back to O'Reilly books, I think :)