I dont know what it is, but Zoe has always been the shit to me, yet she goes against what I usually like. Normally I like a woman a little thicker than her, not necessarily thick, but more than she has. But there is just something about her that does it for me.
Thandie is also fine as hell, but I prefer her when she had a little more weight (like in the movie Beloved).
I wouldnt turn either down anyway, but its definitely Zoe in my opinion.