All I can tell you is I have tried the other detector you have mentioned and a lot of the other big boys like the Troy X5, DFX, Explorer.
I really like the CZ3. I like the meter, the depth (13 inches on my deepest) and around 8 inches on other deep coins. The tone is so sweet and smooth. I love soft tone you hear on deep targets I have not heard on any other detector.
As far as older parks and schools. I hunt every place I can, old & new and the fisher works! It likes new coins, old coins (my oldest 1800 in California). It likes rings and it loves nickels. The high tone is great also. Very stable machine light and balanced. I have been very happy with the money I spent and I use all the coils and they never let me down.
