I can tell you this, which has causeed me to re-think much of what we have been led to belive in the past. Far as I'm concerned, I believe what I can see.
Omega, having a fairly low freq. is not supposed to be good at detecting smallish gold.
However, at least in air tests it will hit a 0.16 gram "flake" at about 3.5 inches. a gold bug 2 for example, and comparrison, a machine designed speciffically for finding small gold (and a very high freq.) will hit the same piece at about 4 inches.
That's with stock coil, and of course little to no DISC. You can not use much (if any) DISC if you are serious about finding Gold.
I've been using Omega for 2 years now. I have access to everything including minelab. I like Omega, it is a very good, one-for-all machine.
Good luck out there.
Rick