My wife and I are new at metal detecting. She started out with an ACE 150 and has moved up to an X-Terra. I have a GTI 2500 and am happy with it although I am still learning to use it. We have kept the 150 as a backup machine. The question is whether the 250 is that much better than the 150 to justify getting rid of the 150 and getting a 250 as our backup.