I did both but it was a long time ago. I read the book and used the CD Rom it came with, and years later took Robert's Glidewing workshop. They were different enough that I recommend both (at the time there was group discussion in the program setup) and the CDs the newer program it comes with are different too.
If you plan to do both, do the book version first, and then the workshop, because the workshop adds to what you learn.