My take: I don't particularly like girls that are oversized. For the two girls in the picture, example, the larger girl is certainly a bit past my personal limits.
On the other end of the scale, I don't particularly like rib bones either. The whole Nicole Richie Jenna Jameson thing makes me ill.
Perfect example is the porn girl Lexi Belle. When she started out, she was, well, thin near pain.
About a year later, suddenly she is much, much better:
Picture 1, she is a cheeseburger girl. Picture two, she is a nice natural 19 or 20 year with a soft sexy body.