I got my Ace 250 July 1, 2010. The only other MD I have before this was a Bounty Hunter with no pinpoint and that sucked.
I have a bucket of junk (trash, keys, lighters, spoons, fishing weights), square nails, a bag of coins, relics and in the last week I've found 5 rings (3 silver & 2 gold) and a silver necklace pendant.
All the rings were found on school grounds near baseball fields. People throw their rings off.
I'm still learning my Ace. But I've learned to dig ALL, if I want to find gold. I run my ACE 250 on Jewelry with sensitivity all up but 1 bar most of the time. If you start to get multiple tones, back down the sensitivity to see what is closest to the surface. Less SENS = less depth.
The ACE will find you coins, just learn it. Do air scan test and lawn test with different metals: nails, foil, pop cans, coins, rings, etc. This will help a ton.
Good luck.