I have only used the S-5 5 or 6 times so far myself but already pulled a rosie 6 or 7" deep that banged hard, and it was between two shallow pull tabs so I'm sure that's why others missed it over the years. Judging by how hard it hit I'm guessing it probably will hit a dime fine at around 9" deep if not deeper. That's pretty impressive considering in my soil only a few machines I ever owned could muster about 7.5" max depth in my soil on a dime, like the QXT Pro...And those few machines were using standard big stock coils like the Whites 9.5". Of course the Explorer got a bit deeper than that, and the GT is even deeper yet in my soil. So, I'm impressed with the depth of the S-5 along with it's separation. Odd thing is I don't think it's left/right field is as tight as the 12x10, but of course length wise it's got much better separation. I prefer a round coil and the smallest one I can find for hunting heavy trash and that would be the S-5 at 5.5" in diameter. Sure, those odd shaped coils like the 8x6 get impressive depth, but I'm mostly interested in max separation and so that means the smallest round coil.