Since the BH QuickSilver was my first and only MD for a while I'll tell you what I've learned about it, FWIW:
The QS can be a decent coin shooter if you learn what to listen for. I probably read the manual cover to cover several times before and after my first hunts with it, and it's very accurate about what to expect from the machine.
Since the QS doesn't give you much info about what the target is, what you're looking for is consistency in the tone you get. If the tone and indicator jump low/mid/high with several swings over the same target, I'm probably leaving it. I dug a lot of junk before I learned that. If it beeps in the same range four out of 5 swings, I'm digging it. (And I'll still dig trash!). Sometimes reducing the depth setting or raising the coil a bit will reduce the indicator jumping around and let you judge better what's under the coil.
I usually ran with only iron discriminated. This eliminates most bottle caps. If you're running in this mode and you get one of those phantom hits that beeps once or twice out of three swings, try turning off the iron disc. and keep swinging over it. You'll find that the indicator is bouncing between iron and higher tones. I usually walk away from those. Eventually I didn't even turn down the disc. when I got a phantom. I'd confirm it with a couple more swings and move on. Did I miss some good stuff? Probably, so start off digging everything. That's the best way to learn the machine.
The QS will almost never pick up a coin on edge, if your swing is parallel to the coin. You can prove this to yourself by pushing a penny into the soil a bit and swinging over it at different angles. It goes to show that if you want to find more stuff, you need to go back over your search area at 90 degrees to your first paths. Overlapping is also important. Some say you want to overlap each swing 50% over the last one. This can be grueling when you're first starting out but it pays off.
A quick story to show you that there's more in the operator than the machine:
I was detecting the towel line of a Florida beach when I came across a guy with an Ace 250. Clearly brand new to the hobby: no headphones, not filling holes, and throwing trash over his shoulder! He lamented that he'd only found 2 dimes that morning, and his eyes popped when I showed him my pocketful of clad!
