I own the 55-200 VR and love it. I also own the 18-70mm and like it (satisfied but not in awe). I'm thinking of eventually selling them both and buying the 18-200 VR. So my question is, will I love the 18-200 VR? Is the lower end better than the 18-70? And, is the higher end the same as or better than the 55-200 VR?