Got a Prizm 4 with the new spider 9in. coil on the way. I will be using it as a backup to my X-Terra 70. Had a Ace 250 but did'nt care for the belltone or nonmodulated audio. I couldnot tell a deep target from a surface with the 250. Hoping the Whites will be a improvement over the Ace. I also hear a new 4x6 coil is soon to be available for the Prizm's. Hope to hear from users of the Prizm on coins. Thanks in advance. Joe