Every spring I hit an area behind a small mall where all the snow from the parking lot is pushed and dumped right after it's melted. A clad and junk jewelry honey hole with just about every kind of trash a detector will hit on. I think it's a real good proving grounds for any detector and coil. The 8x9 coil does an ok job, the 5.75 conc. works really well, and the 8x11 failed miserably with flying colors on my vaquero there. Though i'm no detecting expert but do have a number of hours using all 3 of those coils with a vaquero. I do prefer the concentric coils, the 8x9 and 5.75. I have said before that, with my limited experience compared to some, that the 8x9 coil has hit everything that the 8x11 would have and it does discriminate better. The disc with the 5.75 conc. is just amazing in my opinion. If I had to choose only one coil between those three, it would be the 8x9 though. Just found it to be the better all round coil.