Coming which way? I don't think there has been much quality control issues with later CZ3ds. Will the new ones air test to 40 feet on a dime like the old 1021's? I will tell you that mine won't air test like the experts say it should. I am the original owner and it is under warranty and trust me I will wait until something else happens or the warranty is about to expire before I worry about my air testing score. I love mine, even if it only air test to 9 or 9.5 on the famous air test. I wouldn't be upset if mine did test deeper, but I find a ton of deep stuff, just like it is.
Buy a new one, learn to use it, and months after you fall in love with the machine, do the famous air test. Then you will really be in conflict, if it doesn't air test as deep as you would like, Bottom line, it finds, neat, deep stuff. I sure wouldn't join the "sorry club" who air test the brand new machine and immediately feel cheated. Good luck with your decision. I am going to keep hunting and finding instead of worrying.
Don
HH