I own the Compass XP Pro Plus, which is a slightly better version of the CoinScanner. I also own the CZ-70 which is the digital version of the cz3d. I won't go into the electronics but they are basically the same unit without the digitals - but with a different system of discovering deeply buried old coins.
The GoldScanners (Relic & Coins, same thing) built before Keith Wills' depth modifications got the same air and ground depth as the CoinScanners. After about 1980 the boost went up to at least 11" air, or in Keith's words "they hadn't gotten my circuit modifications". Mine now gets 14" in air on a clad nickel but before I changed a couple of things it got 12". The CoinScanner get's 8" to 9" on the same nickel. And yes, they are all working beautifully, because I was a detector repairman and Eng/tech so I'm not lost when I get inside there.
The cz3d should outrun the CoinScanner for depth, especially in high iron soil or in salt beaches, but it won't out cherry-pick it or discriminate better than the CoinScanner in three light years. The GoldScanner should be a BEAST though!
When you have a lot of scrap iron in the ground the CoinScanner will run like a Cadillac and the cz3d will get nulled so much that it will run quiet a lot of the time, especially if you run it as fast as you run the Compass's. You can take that to the bank. The old Compasses still process mixed signals between good and bad targets better than any other units ever made, including Tesoros and the F-75's. The Compasses (especially the GoldScanner & R&C) will find stuff so small that you will often have to sift sand to find it, and I am serious about this.
The rule of thumb is; Run the cz3d in open fields and on salt beaches, and run the Compass in trashy parks. The cz3d will even outdo the GoldScanners and Relic AND Relic and Coins by 1" on salt beaches.