Hi all! I would like to turn to those who have experience with either the 16-35 f/4 or the 18-35 f/3.5-4.5G lens about a couple of things before I purchase one of them. I know the specifications and have read several reviews of both, I am sure optically either one will be fine for me. I am more interested in their build quality, specifically the damping on the zoom and focus rings, whether there is a play in them, and how well the VR works on the 16-35. How does the build quality of these two compare to other AF-S zoom lenses? (I own the 24-120 f/4G and 70-200 f/4G as a reference, with the 70-200 being better built and much more pleasurable to use in my opinion.) Is the 16-35 much better built than the 18-35, or is the difference fairly subtle? Thank you!