I use the D2 as my primary coil and love it. It has a trait that every DD coil has, it shows bottle caps as quarters. Other than that it is excellent for separation and marginally deeper than the 950. Side by side, the D2 can find targets that the 950 has NO chance at finding due to the fact that targets close together will cause the 950 to mask and null. I combed my small yard over MANY times with the 950 before I owned the D2 coil and dug every good target I could find. Once I bought the D2 I have gone over my yard and found several silver dimes both rosie and mercs, V-nickel and several buffalo nickels that the 950 could not detect. But not because they were too deep, they all had trash near them that masked the signal. Many public areas have been hit HARD in the 80's and 90's. But most of them used concentric coils and missed good targets that you can find with the D2. When I get a trashy high tone chirp with iron or foil signal mixed in, I slowly try try separate multiple targets and many times I have been able to tell "yep, there are two targets there".
