I have read previous "Head First" books, and I cannot recommend their style enough. They manage to get across a lot of technical information but in a comical way that helps (me at least) remembering it.
Of all the technical books out there, I find "Head First" the most readable. Chapters are self-contained logical units that can (if you want) be read in isolation, and as well as explaining what the design pattern is, it also explains which OO principles are in play.
The book states that it isn't suitable for design pattern "experts", if you have (and memorised :)) the GoF book, then the implication is that you won't need this. I actually disagree. I am pretty familiar with most design patterns out there, but I still gained something from this. Even if I knew the pattern, this book made me think about the rationale, the application and why it was good from an OO perspective. Or at least which OO principles were being applied.
Just to be clear; GET THIS BOOK! If you do not know what a design pattern is, this book will certainly be easy to swallow then the other dry anaemic design pattern books. If you know all the design patterns going, then this is a refreshing reminder.
P.S. Yes, OK, the cheesy style does get on your nerves a little bit, but it is worth it :)