This book really helped me for a beta exam I took as "Guinea Pig" for the upcoming ZF2 certification. The thing is, I have experimented with ZF2 before, picked up some bits and pieces of information but never really grasped the core idea behind ZF2. I remember in one of the sessions at ZendCon EU, there was a slide that said something like "dependency injection is a $25 term for a 5 ct. concept". That describes best what happened when reading this book. It all suddenly started making sense - I was no longer put off by terms that did not have any meaning to me, but started to see the big picture and these technical terms just became obvious names for what they stand for..
Before reading this book, I was afraid that at the exam I was going to be confronted with questions that would make me go "WT*?" - but after reading the book every question made sense. I may not have been able to answer them all correctly, but that would be a result of not enough "hands on" experience. I estimate my score will be just under or just above the threshold, I may not have excelled but definitely don't think I failed big time either.. Thanks to LearnZF2 :-)