My 6 year old son loves these books, and I'm impressed with the content. The names of the pokemons are mostly variants on real words, with abilities and traits that go with the real word. Rampion goes with ramparts, Shieldon has a shield head, etc. It's an interesting vocabulary builder, and a more interesting way for me to talk Pokemon with my son.
Unfortunately, the binding is cheap and inadequate. This binding is perfect for notepads, where you are supposed to remove pages. It's terrible for a book for little boys. We returned the original set we received, but had the same problem with the replacement. Volume 1 started losing pages within a few hours on both sets. Volume 2 has held up better (and it has certainly been put to the test). Fortunately, the pages don't really need to be in any order unless you are trying to find a specific Pokemon, so it hasn't really hampered his enjoyment of the book.
So, if you have a die-hard Pokemon fan who is willing to shuffle pages instead of flipping them, or if you can find this book in hardback, I'd recommend it.