I didn't actually run a test when I had an AT Pro against the Deus, because I had them at different times. The AT Pro went fairly deep, but I know that I was getting a consistent silver dime air test out of the Deus at the 8-9" mark (estimate) with the 9" coil. It is a deep detector.
I would go as far as to say that it was my deepest, repeatable signal detector out of the most recent ones I've used (AT Pro, CTX, CZ3D, Etrac, Vanquero). I hit a small yard really hard with an AT Pro with the (5x8 and stock coil), CTX with (stock and 6" coil) and Etrac (stock coil) and I was just able to squeeze out sounds at 10 inches with the Deus (9" coil) and they were wheat cents. This is why I want another.
Oh, to add some additional credibility, the yard is 25' x 30' and the signals were not consistent with any other machine, but consistent enough with the Deus to warrant a pinpoint and dig.