graveler,
Use both!
You've probably noticed that in Ferrous you have to look at the screen for everything you hear just to know how conductive the target is. That's the drawback to Ferrous.
In Conductive when you get a high tone it's telling you coin or other high conductive target.
In Conductive you can focus your attention on hearing and then use the screen for confirmation if necessary.
Lots of places have so many nails etc. or high conductive rocks/minerals that ferrous will help you find
non iron better than conductive. You're not hearing 150 high beeps a minute like in conductive at these places.
I highly recommend getting used to both. And know what the sounds mean in both.
In FERROUS:
lowest pitch tones mean iron and anything above the lowest couple of notes is NOT iron.
In CONDUCTIVE:
lowest pitch just means lowest conductive(foil, small aluminum, small anything)
middle pitches are (tabs, gold, nickels, aluminum, flying eagles, fatty indians, many tokens, lots of jewelry etc.)
highest pitches are highest conductive(silver coins, silver rings, indian cents, large cents, pop cans, belt plates, big aluminum, big keys, heel plates, many tokens, etc.)
When hunting in conductive sounds don't worry about the left to right reading of the cursor or the ferrous numbers if you're using numbers. They don't mean much except to tell you how possible it is that the target is iron(cursor pegged left).
If you have to have a 100% positive ID on something before you'll dig a hole then you should wait a couple more decades before detecting because they don't make a machine that does that yet. If you have a site that gives up good old stuff then dig all kinds of signals.
Hope this helps,
Neal Wright