The transcriptions are bang on; that's also the only problem I had with this book. All of the songs are very difficult to play- I guess by necessity, given the nature of the musical form and need to capture Joplin's syncopation.
I'd recommend Fingerpicking Bach as a starter. There's a good mix of simpler tunes with more challenging ones. But if you're an accomplished picker, this book will give you one heck of a good way to impress friends at parties, as well as give you some ideas for spicing up your playing generally.