I bought my first detector back in about 1972, and it found coins at 2" in the ground. I built my first one in 1974, and it did likewise. Then I bought a Garrett Deepseeker and it would find corroded pennies at 10", in high salt/high black sand beaches. Nothing I have used since that time, regardless of which brand, which model, multi-frequency, single, PI, or anything for that matter - has ever outdone that old Garrett relic for depth. And yes, it was in all-metal.
When I hear people say things like "I dug a penny or dime at 12", or 15", etc, in high iron red clay soil", all I can do is shake my head and read something more rational, like "UFO's are landing Tomorrow". One guy got really angry at me (and others too) because we didn't believe his Minelab Explorer found a clad quarter at 42"!
The best depth I've seen in the really nasty soil in the last (20) years is a CZ3D or CZ-70 @ 8". The best I've (ever) seen is the old VLF Deepseeker @ 10", but that was 37 years ago. The best I've seen in almost zero mineralized (sawdust) soil since then is 10". I have never in all my life seen more than 2" difference in coin ground depth of ANY detector in average ground, regardless of brand, type, or cost of the detector. All I can say is that sometimes detectorists have some really big imaginations, or they are......?
BTW, for what it's worth, LowBoy was using an AT Pro trying it out, sold it, and overwhelmingly prefers the G2. LowBoy KNOWS what he is doing too. His videos can be found on You Tube.
LL