I found that interesting, actually, esp after couple minutes of really comparing the images and thinking about the lighting changes.
One thing that stuck me is how although I am not a big fan of blue backgrounds, I found the blue in the second background really was nicer than if it had been just a gray. The text says gray, so I don't know if it was the wb or what. But the same image with a total gray background would have been less appealling to me.
It would have been interesting to see that same shot but with grids on the front softbox as well to see the difference. I know that is not the look you were going for, just curious on how it would change the look.
I am drawn to the third shots the most though, with the high contrast. Just a personal thing.
Thanks for the time to post and explain your setup.