Hello Bryan....bottom line, larger the coil, the deeper it sees, and the wider it scans! Draw backs, in trashy areas, some times the larger coil sees "too much" i.e. trash-trash-trash. Some like to use the smaller coil in that scenerio. I prefer to hunt with my 10.5" coil, 95% of the time. Like with any detector, learn what the machine is telling you...learn to speak the language, and the sky will be blue, and the sun will be shining. Learn the tones the Quattro sings to your ears, and your success ratio will climb dramatically. I only use the target ID as a confirmation of what my mind has deduced from the sounds. The Quattro needs to be swept a little slower than many, to give it time to recover from bad (nulling out) to good, pure, clean audio tones on the keepers. The larger the coil you use, the slower you need to sweep it. You will be very hard pressed to find a better machine though.....and you can take that to the coin bank!
Chuck@TreasureHut