You're gonna LOVE the Omega, Farscape. G-R-E-A-T bang-for-the-buck IMO

As you said, it is a loaded weapon on nickels and coins in general. On coins, a realistic depth would be a solid 8" to 10" max (at least in my soil)...which is pretty darned reasonable for a $600 detector.
Here's the thing though, as you already know, the Omega also LOVES junk. Especially deep iron (nails, screws, etc.), small bits of aluminum & of course the dreaded bottle caps. X'ing the targets did little good for me most of the time since some of the junk sounded so damn good. I'm also a fast hunter, so, fiddling around with all the "tricks" to help decipher what was or wasn't junk just wasted too much time. So, I would just dig away on anything that sounded halfway decent and had a fairly stable VDI number (within 5 or 10). Anything else was trash 95% of the time.
I believe the Omega to be one of the lesser known, under appreciated, "hidden" gems out there. The speed is lightening quick, manual G.B., notch discrimination, 99 segment VDI scale, frequency shift, an assortment of coils available, light-as-a-feather & operates on one 9V battery. Need I say more?!
I would NEVER get rid of my CZ-3D. Best machine I ever owned. However, there's a reason I still have my Omega
I love it already, coins deeper than 7-8 inches in my area are very rare. I found 3 coins at 7 inches within 3 days of owning it and that's good for here. I haven't had any problems at all with deep nails/screws..shallow rusted bottle caps were a problem til I found out that really bouncy and high 90's numbers have never been coins for me so I just pass them by. The highest number I've ever found a coin at is 91. Basically I only dig 56-57 and 77-91. I am also a fast hunter, especially with the Omega as it's very light and comfortable with super fast recovery speed. We should try to get a chart together on what certain targets ring up as. I haven't found an indian head penny yet, I imagine it would be a high 70's number zinc/penny range but not sure. Also haven't found a buffalo with it yet so not sure if they ring up 56-57 like jefferson nickles.