Choosing objects of color different from the main objects was a good choice here as it makes them stand out more in addition to the effect of the DOF. I like the composition as well as the lighting. For some odd reason, however, something is slightly off about the picture. I'm gonna give it a 7 until I figure out what it is...
This works as a high key but the whites could be a touch whiter. The subjects are pretty, but I'm not sure about the composition. a different arrangement would have worked better here I think.