When swinging over 10-11 inch coins, while walking in a circle, in my test garden, They sound like iron for about 60% of the circle.
So deep nonferrous targets will sound like ferrous targets at the right angle.
I have also found this to be true while in the field.
As for the 3030, yes I dig more rusted square nails with the equinox by a long shot.
The advantage I have over some is that I mainly hunt farm fields and I can quickly dig and not have to worry about plugs in a yard or park.
And in my experience Park 1 gives a more stable ID than Park 2.
Park 2 seems to have a better audio report but on my 10 inch dime the VDI bounces into the single digits.
While the VDI in Park 1 jumps a little high but is more stable.
I know some will have a different experience but that's mine.