I bought a DFX for relic hunting last year. I quickly found out that my Tesoro Tejon was a much deeper machine. Kind of knew that anyway. I dug a real deep minnie and it fell to the bottom of my hole, which was about twelve inches deep. My buddy who had a DFX said, wait a minute, let me run my DFX over it and see how it sounds. It didn't sound at all, nothing. I also had my DFX and I ran mine across the hole and nothing, I tweaked it a bit and barely got a tone. My Tejon was picking it up loud and clear. Within two weeks my Tejon was sold on Ebay.
I might add that the Tejon seems to work exceptionally well in really soaked soil. I did my deepest minnies when the soil is saturated. In fact dug a half dime on Friday in an area the size of a large bedroom that I have gone over at least one hundred times in the last three years. It is where I cross the fence from the road so every time I go there that is where I turn my machine on and start hunting.
I think the DFX is more of a coin machine.