I just picked this up yesterday and was so excited to use it! I've now found a new bronzing brush. Whooo! I was using their 129 as a bronzing brush but I noticed it was leaving noticeable streaks and well...the head of the brush was just too dang big. However I'll use the 129 for applying bronzer to the rest of my body.
I've also used the 187 to apply strobe tint to my cheeks and will try applying foundation with it by blending Fix+ spray with foundation. MAC Pro makeup artist Matthew Arbogast told me that it gives flawless, almost plastic-like, skin.
If you use bronzer on your face or like applying shimmer/highlighter but don't want big chunks of it everywhere and more of a natural "glow", do yourself a favor and pick this up! Fortunately I get a discount (PPID) so it was super cheap for me. But I would pay full price!
UPDATE: I have started also using it as a foundation brush and it gives the most flawless complexion. I use some liquid foundation in the palm of my hand, spray 2-3 spritzes of Fix+ on top and mixed it together with the 187. Then I start "buffing" it onto my face, with small circular motions. The result is a completely flawless complexion that makes you look like you've been airbrushed! Try it. :D This has got to be the most versatile brush I've ever bought. I'm tempted to buy another one! Retails for $40.