Yup, there will probably be a big difference between an Ace 250 and an XT70.. had both. If you plan to do any prospecting, and want VID/TID in your detector, the XTerra 70, Fisher F70, MXT/M6 would probably make for the most appropriate mid-range choices. I wouldn't go the Garrett GTI route (binder dundat) as the GTI 2500 doesn't have the small gold sensitivity as the others and the all-metal mode doesn't handle nasty ground (highly mineralized and changeable) all that well. As a coin shooter, on the other hand, it's one of the best and hunting in AM mode with the imaging on is really handy (and deep). Of the others, the MXT would make for a better prospecting unit in bad ground than the XT70 while the XT70 makes for a better coin/ring hunter. The MXT also seems to have a slightly more sensitive disc. mode than the XT70, though I'm talking very slight. The F70, judging from my F75 would probably give the MXT some stiff competition in the nugget hunting arena. It would also make for a better coin/ring hunter. The nice thing about the F70/XT70 is that you can put it in multi-tone and spend more time hunting and less time watching the meter. Also, I found the fixed notch on the MXT to be next to useless. One area where the MXT rules supreme, on the other hand, is coil selection. Both the F70 and XT70 have a pretty poor selection. I can see the F70 getting more and better coils (I hear that there's a HUGE SEF coil available) whereas Minelab has pretyy much shut down after market coil production for the XTerras. Also, both the XT70 and F70 will probably spend more time on their sides than upright due to the dumba$$ form over function philosophy exhibited in that aspect of their design. The MXT, on the other hand, is rock stable. There are many more pros an cons that I could list for each, but my fingers are getting tired. ..Willy.