Howard, I'd like to be respectfully contrary; my experience and knowledge of these matters pales in comparison to what you (and Stan & Richard) bring to this forum. However, consider the below shot from my gallery: taken with a D7000, handheld, 400mm, and 1/200th shutter speed. Clearly, VR did its job. Looking only at sharpness, it seems (to me) that this image is sharp.
Maybe I just got lucky. Maybe it's not as sharp as I think. Maybe VR explains everything - and maybe one lesson I can walk away with is that VR really is that important in my hands.