Blue Duck.
I don't know if there is a good answer for your question.
If your looking for gold get one that is build for gold and the price you can afford.
You must take into consideration the soil your working mostly, make sure it has good ground balancing and rejection.
I started with the Minelab 3500 and it has payed for itself in a short time. I have never been sorry for spending the extra money.
LP