I like the 224 for blending, a sublte wash of color in the crease, and for adding a touch of color to the outer-V. I like the 217 for laying down color on the lid and blending. I wish I had 5 of them, seriously. And it is also great for paints.
Just wanted to update and say the 217 is awesome, it is so much better than the 224! The 217 is much easier to blend with, and it can be used to get that nice wash of color. It is much more easier to handle and use in my opinion!
I'm asian and I have no eyelid folds. I have both brushes and I rarely ever use the 224 for blending. It's too flimsy and just doesn't blend well enough, due to the shape of my eye. The 217 is much, much better in my opinion.
I guess I've come to the conclusion that I will just end up buying the 217, 222 and the 224 all together. Otherwise, there is no real way to decide which I like better for which applications or jobs.