Richard,
The C$ may eek out a few coins from trash that the 3D won't see, BUT they will not be the nice solid hits that the 3D gives on most coins. The tough ones I find with the C$ are the kind that do not repeat on every swing and the ID will vary by quite a bit. Nickels are the worst. To get the ones that other machines miss, you gotta dig signals with wild swings in ID because nickels mixed with iron are very hard for any machine to see let alone ID properly, the C$ tries its best on those and you know something non-ferrous is there but no idea what. For example, I was hunting an old one room school where the finds were next to nothing over the last year and got one of those wild bouncing ID's I grabbed the ML Advantage and the signal would repeat with the disc set at 11:00 and by 12:00 it was gone (normally buffs and even V's will hit at a 2:00 setting on the Advantage) 4 nickels later (2 buffs and 2 V's) and there were no more signals in that small area. I had been over it many times with all my other machines from all possible angles. I highly doubt the 3D would have given a high tone on those nickels. Dimes in iron are another good example, you may see a high coin reading occasionally but the tough ones won't repeat on every pass even when you do your best to center the targets and when it does its just a quick tone and a high number that can vary a couple either way mixed in with the iron readings and tones.
In a nutshell the C$ gives you a indication on coins that others pass up but they are not normal "diggable signals" .
For me thats exactly what I was looking for in a machine.
Tom
