What is a better metal detector?

a href="http://cgi.ebay.com/Whites-classic-2-Metal-detector-/130477027601?pt=LH_DefaultDomain_0&hash=item1e61097111http://cgi.ebay.com/Whites-Coinmaster-IV-metal-detector-/290524531481?pt=LH_DefaultDomain_0&hash=item43a49c8b19http://cgi.ebay.com/GARRETT-ACE-150-METAL-DETECTOR-NIB-FREE-SHIPPING-/370474943699?pt=LH_DefaultDomain_0&hash=item56420704d3" rel="nofollow"http://cgi.ebay.com/Whites-classic-2-Met…/a What is the most accurate to detect coins and gold.