The Workbook for the 15000 Quiltmaker Edition is a very nice workbook, and can really help a sewist get hands on experience learning their new machine.
This is who I'd recommend it for:

• a new sewist or
• someone who really wants to make samples using the various functions available in the machine.

I wouldn't necessarily recommend it for:

• an experienced sewist or
• who has many other books about sewing in their personal library
• one who can figure things out on their own or uses the Machine Manual to figure things out

It is composed of many exercises to make samples. It's well written and has a nice presentation. It's price is fairly high in my opinion, but that comes with a bias based on the fact that I have been doing those techniques for 40+ years!!! 
So, that's my two cents worth!
Faviola