Double "d" search coil

[Inspector]

I may potentially be buying a double d eliptical coil and just want to make sure I understand some things. First the coil maximum depth is slightly reduced in comparison to a similar sized concentric circular coil. Second because the coil is long and not very wide more area can be covered more completely per sweep. Third double d coils aren't as sensitive but do better in mineralized soils then concentric coils. No motion pinpoint mode, now the whole center bar is "hot" should be rocket science to pinpoint if you know that :) Any comments from those with a lot of experience using concentric and double d coils?