I've bought a lot of eyeshadow brushes and this is the best of the bunch. It is narrow enough, rounded enough and tightly packed enough for perfect shading in the crease. Beats the many Sigma crease brushes, rounded and pointed, that I've collected and most of the Real Techniques ones. This is definitely worth the money and wish I'd discovered it sooner. If you have this brush, a flat Sigma shader for laying down lid shadow, an angled brush for eyeliner/eyebrows and the biggest fluffy brush from the RT basic eyes set, you've got all you need without spending a small fortune on MAC. And this is synthetic which is a bonus not only because it is cruelty-free, but because if you have horse allergies like me, hairs from most hoofed animals (goat is popular in the white makeup brushes) will make your eyes itch. It took me a long time to figure this out! The synthetic brushes used to be terrible, so if you haven't tried one in a while, start with this. You'll be impressed.
This brush makes eyeshadow easy to blend, the bristles is so soft, more soft than my mac brush. Worth every penny.
Hourglass brushes are truly worth every penny and many more. I've actually got two of these brushes and would gladly buy another. This brush is amazing for doing everything -- blending in the crease, applying color to the lid/inner corner/brow, or smudging shadow along the lower lashline. The only brush I may use other than this is an eyeliner brush. This is synthetic, so, it can be used wet or dry. I wouldn't go without this brush ever again and won't go back to natural hair.