Larry, I agree with your description/comparison of DD vs concentric coils. And when your in a good area, the VDI accuracy, or inaccuracy, isn't a pro/con issue for me because if it showed a bottle cap signal I would dig it anyways. Even in a modern and active park those bottle caps should be dug as well. Lately, I've only used the D2 and covering areas I had already dug all the good signals I could find with the 950 and I am finding many more targets that only a DD can separate from the iron targets near by. A large concentric coil designed for depth is completely handicapped if there is iron right with the coin and even ground mineralization greatly effects a large concentric coil. The targets that a concentric coil is able to find are what I would call easy target, most of the old easy targets are already dug in areas that have been detected already. In order to stand a chance in finding 1800's coins in an area already detected, which is nearly everywhere, you need a coil that can find difficult targets and separates well. I am finding silver pretty regularly now that I am using the D2. I'm at peace with it showing bottlecaps as quarters, it makes up for it. In the past few hunts I have dug a barber half dollar, half dozen IH cents, several V nickels, several silver dimes, all in areas I covered heavily with the 950. All these areas also open to public and other detectorists on a regular basis.