The head first approach depends on a lot of images, since an image says more than a thousand words. It also depends on repeating the information in different styles, and dialogue like text.
Even though this might seem as if it's a very simple approach, but the result is amazing. The book is fun to read, full of information, and yet very simple. Never thought I would love to study that much again.
Few mistakes are there (like any book in the market), but most of them are spelling mistakes. The O’Reilly website has a great errata page covering every single mistake in the book (even spelling and grammar mistakes).
A lot of topics covered in the book do not even appear in other books, and a lot of those come in the exam. I studied from that book, and got 94% in the exam. Great book, and really fun to read.
Buy the book from amazon.com