Thanks for all the great advice. I tend to favor the 950 and 5.3 coil followed by the 4x6 and 12" super coil. My least 2 favorites are the 6x9 and 1400 DS. The ground I have been hunting in is usually around the mid 70's so the mineralization is higher but I am getting better results with my 5.3 coil over the 6x9, so I totally agree with Monte on this issue of the concentric coils. I like Larry's thought on replacing the 1400 with the D2, the 1400 is a tank but it has excellent sensitivity to small objects for being such a large coil and great coverage, although I have not found it to get much more depth than the 950 coil even in mineralized ground.
That leaves the 6x9 eclipse, I was thinking about replacing this coil since I am no longer in CA hunting for gold nuggets, now I am moving to England in a few months and I might have wait and try the ground and decide which of the two to replace for the D2.
I tend to stay away from after market coils, but just out of curiosity are they any better than the excellerator coils made a few years ago?