Why, the one that finds all the gold and silver of course lol All kidding aside, there are a couple of choices that I know of. The Excalibur from Minelab, White's Surf PI Dual Field or the Beach Hunter 300, and the Garrett Infinium are some of them. Each probably has a good learning curve, so a test run from a dealer or an experienced water hunter would probably be a good idea. Also discriminator vs all metal is an issue too.