Well two flaws really:
1. The Guitar Chord Songbook series is notorious for making multiple books with the same songs appearing here, there and everywhere. So if you have 3 different TGCSB's then you will probably have at least 20 songs in more than one of your books.
2. No CD = no help with the strumming patterns in songs and a good deal of the songs are obscure so you often find yourself flicking past 9 or 10 songs just to find one that you know!
Having said that, they are easy to read, they are accurate and they can often introduce you to awesome songs that you've never heard of before. You can basically find all the songs you don't know on YouTube if you need help, but this kind of defeats the point of having all of this in a book since if you have the internet you can find all the chords you need online.
In short, you'd better know a lot of the songs in this book if you want any practical use out of it.