I just bought my F75 SE about two or so weeks ago. I had an F5 a couple years ago, but sold it and bought an Etrac. So far, I prefer the Etrac for coin hunting, but I just don't have enough time on the F75 to compare yet. What I can say is the machine found two small flakes, smaller than a match head, on the north yuba. I had the boost on, sensitivity all the way up, and discrimination around 12 or so with the 5" DD coil. I tried in JE and DE modes (mainly due to the machine chirping a lot), but boost does seem to give more depth on smaller targets (about 1-2" or so on such small flakes). Wish my buddy Frank was there I could have compared the F75 to his MXT with the bigfoot coil.
Figure if I can hit smaller than match head size flakes at 1-2", I should be able to hit a picker or nugget much deeper. I used the f75 after we had started clearing out an area to point me in the direction to dig. The two hits were not right next to bedrock, but about a foot or two away from it. I can't wait to get back there to strip the over burden and get some more detecting in!!!