Previously I am holding a Nikkor 70-210mm f/4-5.6 AF-D, this lens is fast and sharp for me. But recently Nikon announce a new lens that is 55-200mm VR. I wonder is this a good time for me to upgrade? Will the VR help alot? I never try the 55-200mm VR, does anyone compare this two lens before? Because what I worry is the 55-200mm VR is not as fast and sharp as my 70-210mm. And also, I did saw some comparison the bokeh of this two lens on web, and seem like the 70-210mm lens bokeh is better.