Different soils... whatever. Like Elmy, I'm going to sell the Nox. It finds silver, but also leaves it in the ground.
Found a merc coin spill with the nox-- took two mercs out of the hole. Hunted a 10x15' section from 6 pts of the compass, going slow. Went over the plug many times. Came back two weeks later, showed my kid where I found the two mercs, and he promptly pops a third out of it. Stuck the coin back in the hole and the Nox didn't even give an iffy signal-- and I played around with every setting. Same with a copper hexagonal bar token. Nox totally missed it and didn't give a decent signal-- both coins 5".
What made me take a scientific approach to it was a hail mary dig on what turned out to be a 4" seated quarter. Totally egregious-- a 4" silver quarter with my etrac would have shattered my eardrums.
Imo, it's a nice, all around detector. It's a sweet beach machine. But having double fisted the nox against the etrac and ctx-- where I hunt it comes up short. I've spent over 200 hours on the machine now-- my other machines have found coins it has missed; it has not found coins the others have missed.
I will say that the ATPro, in my area, in the hands of my kid-- Ho Ree Phook, he siphons silver.
If I were on a budget, I would be weighing the Fisher F75 and the AT Max. Ronstar's Fisher has tallied gold and silver in fantastic quantities.