EZ2Find, I have a CZ20 and really like it, it is the easiest detector I have ever used, and it is tough, mine has taken a beaten and it's still ticking with no problems, I hunt mostly Ormond Beach & Daytona Beach, and a lot of inland too, like parks and picnic area and RV parks.
I have the 8" coil on mine, that helps in the trashy areas, but at times I wish I had the 10.5" for the beaches, and then again I am glad I got it with the 8" because the currents have less pull on it, and believe me that takes a toll on the arm in a few hours.
As far as iron being a problem, it is not a problem, some area of the beach is infested with pieces of iron the size of a pin head to a half dollar, I never use the dis. even in these areas, I hear the low bonk tone I know it is iron or junk, and move on, when I first got the CZ20 I would dig the low tones and it would be junk, just learn the tones, and how they react and the CZ20 will reward you.
I have hunted behind Excalibur and a lot of other detectors that have gridded the area, and also found silver and jewelry they have missed.
I use the bobbing method for ground balance and that works fine for me,I must warn you the cz20 is one deep seeking machine, and by all means get a chest harness, they work great and only cost around $20.00 to $25.00 Hope you enjoy your new detector, and Merry Christmas, Bernie