I have a 5x10 DD Coil and it works pretty good. I was skeptical at first when looking into a new coil but had to take the shot. Lot of trashy areas up here as well. I would say stick to the 8" concentric when the ground is drier as the 5x10 is pretty iffy during that circumstance. So much so that when I first ordered it and put the 5x10 to use this past summer, I gave up and went back to the 8" concentric. Our ground up here is predominantly iron rich. With the Delta 4000 I've found that the 5x10 gives me a tighter spot and about 2 to 3 inches more in depth. The photo was a find from 12-16-12 in an athletic field with the 5x10. It calibrated in at a STRONG 59/60 in a VERY tight area. If the signal was not as strong as it sounded, and as tight, I would have suspected a pull tab or possibly a nickel. But at 3 inches down it was SCREAMING, so to speak. And I bulls eyed it with the first plug, very hard to do with the 5x10 if you don't take your time and 90 degree sweep a spot. I use A2 all metals almost exclusively with a sense setting at 10, sometimes 8 if I have a lot of EMI to deal with, and the volume at around 6. I started working with it again since before SANDY and can't say I've wasted my money. But it takes practice. A lot of field time. Found a few silver rings as well. And one 925 silver lobster clasp about the size of a stick match head with the 5x10. So it works. Numbers are a little higher by 1 or 2 points so it does take some getting used to. Good luck with it if you make the decision to buy.