Great question and of course I am very biased.
I think Android in Action is best for people who have some programming experience. This is not the best book for someone new to
Java and software development who wants to try to learn by making applications for phones. Hello Android might be a good book for those people. I think where this book excels is:
1 - very up to date code including notes and references for 2.3. BTW make sure to first download all the code in that some chapters do not show complete code listings, such as import statements, so its important to download the code to follow along with this book.
2 - wide breadth - we cover everything from getting started with Android to building Web Apps with HTML 5 and using the Native Developers Kit to use C or C++ code bases.
3 - depth of coverage - some books have deeper coverage on a single thing like UI in Android, or some specific feature, but most of the coverage in this book is deeper that just a basic example. There are several sophisticated, real, and working applications in the book and one of them, that allows you to drive lego mindstorms from your Android Phone, was submitted to the App store. As such this book is not only a good developers book and a good reference but will give you a real understanding of what you can do with Android making a serious application.
Thank you,
Robi
