While there are tons of other RoR tutorials out there, they all usually reach a point where the gently increasing learning curve suddenly goes vertical. Not so with this book.
The author doesn't make things overly complicated, makes it clear when you need to be aware of new concepts and when not to worry (because it'll be covered later), and while this book does follow the traditional "develop an app while learning" method, it does so while introducing you to tools and techniques that Rails developers use in the real world. Before you know it, you'll be creating new git repos, pushing them to Github, creating branches for new developments and using test driven development (with tools like Rspec) to test your new code. If most of that went over your head *and* you want to learn Rails, you *need* this book.
Interestingly, he demonstrates how you can create working Rails apps with a minimal knowledge of Ruby - which kills the assumption that Rails neophytes need to have a strong grasp of the Ruby language before tackling Rails development.
Combined with 15+ hours of video lessons complementing each chapter of the book, this makes for an essential tool in the arsenal of any aspiring Rails developer.