With my new pattern, Barely Beret, I like seeing the detail on the mannequin's hat, but I also like seeing how the hat looks on a "real person."
So I'm running a little -- admittedly unscientific --test: In my Hats by Elvee shop on Etsy, the lead photo for the pattern is with a mannequin. In my Provisions by Elvee shop, the lead photo is of the model.
As of now, the model listing is slightly ahead in views. Stay tuned.
Edited to add 09/03/13: The model is still ahead in views -- about 20 percent more. Interesting....