Get a Minelab explorer II. It's deep, and retains respectable TID to the deeper depths of its reach. I'm sure there's machines that a) go deeper. And b) have better ability in trash/iron. However, it's a question where ....... when anyone asks about "depth", you have to ask: "At what cost?". Because machines that might go deeper, or fare better in iron/trash, may lack reliable TID (you might get fooled by iron a lot, or you may be at a disadvantage when TID comes into play - like park turf, where you might have to be more .... uh ... "selective" of what you choose to chase, versus pass). Or some machine reknowned for deeper depths, hit a brick wall in soils that are more mineralized.
But all in all, the explorer II (or any of the various incarnations) are good all around coin/relic machines.
The learning curve is steep though! The sounds of the flock of sick geese will drive you nuts at first. Hook up with a proficient user, to trade off flagged signals. That's the only good way to learn that machine (saves a lot of time in the learning curve)
