The Ace is a good unit. My hunting buddy hunts with an Ace 250 that he bought at a pawn shop. I hunt mostly with a T2 and the Ace hangs pretty close.......he dug a wheatie at an honest nine inches lately.....top soil.
I know a lot of people talk down the ACE 250, however, I have the 250 and I simply love it. I have found everything from silver coins to wheat pennies to every other denomination of coin. It goes up to about seven to eight inches no problem. I just purchased the DD coil for it and it works well for me.
I think it burns some people that paid over a grand for some machines when the 200 dollar machine makes some finds just as good. I have the ace 250 a am happy with it. Just because its yellow does not mean that it doesnt make good finds too! Believe me it does make good finds. Ive had mine for 6 weeks and have found lots of good things.
Some have said it lacks depth. The ground around here is so hard sometime when I get a 6" signal I make sure its a good one before I dig because its not just a hole, its a commitment.