Couldn't help but put my 2 cents in here. My 3 year old daughter was given this book about a month ago and we've read it at least 5 times a week since.
She has a bookshelf full of fun books (pop-up, little golden books, dr. suess etc) but she chooses this book again and again.
I just noticed this week that if I start a sentance from the book, she can finish it w/o hesitation. We went thru the entire book this way. At age 3, she's saying things from the book like, "they are one for a penny", "how much money do you have"...hearing a 3 year old talk about arithmetic is also amusing. She can almost recite the entire book, just about word for word, and she's only had it a short while. I can certainly see the potential here and I never say no to reading it. She can now spell cat and is working on dog. It really is all about repetition, and this book allows just enough details to keep parents reading it.