I'd go with the 217 brush. It's a great all-purpose shadow brush that you can use to just apply shadow with, too. I find the 224 a little lacking in the department - maybe just a wash but nothing intense.
Also, the 224 is HUGE for my Asian eyes. I mean, I can blend a decent crease in there but it's sort of ridiculous how large it is. I think maybe a 222 would be a better option, but I'd still recommend the 217. I feel it's much more precise.
Does anyone else have a problem blending with the 224? I know it sounds ridiculous since it is a blender brush and all, and everyone seems to love it, but it is one brush that I can't really get behind. I cannot blend with this brush! I try and I'm still left with a harsh line. Annoys me to no end...like I'm doing something wrong! I feel like it's too flimsy to do any hardcore blending. That's another reason I prefer the 217 for that because it's stiffer and gives you WAY more control, even in blending.