I finally bought this holy grail brush MAC 217. It is a tad bigger than I thought. The bristle is full and thick goat hair, multi purpose and easy to wash and dry. I am glad to add it to my brush collection.
I bought the Mac 217 brush after seeing that Lisa Eldridge couldn't live without it. The product looks to be good quality (I've only had it a week so I can't speak to its long-term quality). The bristles are soft and they blend beautifully! I am an experienced makeup artist myself after working for Chanel Cosmetics and I must say, although I love the Chanel shadow brush #20 for creating great shape, the Mac 217 gives much better diffusion of color and works beautifully for subtle layering.