I really enjoyed Al Capone Does My Shirts! I found all of the characters to be engaging, believable, and capable of inspiring an emotional reaction from the reader.
The book falls into kind of an interesting place for me. On one hand, it does lightly allude to some kinda sorta mature themes on occasion, making me not sure whether or not I'd want to recommend this book to my eleven year old niece (I'd probably give it to her mother to read first). On the other hand, I can't imagine this book really speaking to kids much older than Moose, the main character, who is in 7th grade. I think there is a very tight window where this book has the greatest chance of appealing to kids, and I do think it's a well done book very worth reading, so if your'e on the fence about suggesting it to a kid, make your choice quickly. I do think the book could appeal equally well to boys or girls--I definitely didn't get the feeling that this was trying to aim itself at either gender in particular.
The audiobook was well narrated by Kirby Heyborne. His style was engaging, and his voice acting for each character was very well done. I am definitely looking forward to reading Al Capone Shines My Shoes, the next book in this series.