Yes, I've done the Artist's Way and the workbook. In the winter of 2009, my friend and I met every week for breakfast and discussion of a chapter. We shared our workbook entries and our challenges, troubles, and successes. i really enjoyed the process.
I found the book interesting and somewhat provocative, but it didn't change my life or my work. My work has always been intuitive and organic.
I see designs everywhere I go, in architecture, tilework, furniture, flowers, tree bark, grasses. I often dream design ideas or color combinations. I wake up and sketch or jot notes of the dream. I've always felt that art is a natural part of living, like breathing, and it's still that way for me. The book reaffirmed that feeling.
But my friend felt a huge change-- a release-- after we worked through the Artist's Way. She's more open to possibilities now. she takes chances, she feels free to try and to make mistakes and do over, and that freedom has informed her work.
I would recommend the book and workbook. It's worth the time, and it may be really helpful.