Hi,
i have had both machines at the same time...i just sold the 250 and still own the m6....the 250 is a capable machine but had 3 things i did not care for...first and foremost is the annoying bell tone response the unit gives(Just my pet peeve...others don't mind the sound) i could not stand the sound it made over a good target...secondly the machine only shows targets as notches. for gold hunting i prefer a vdi machine to further aid in sorting out gold vs. pulltabs.....lstly the 250 lacks groundbalance..That said, the machine still works well and consistently will hit coins at the 6 to 8 inch realm....as for the m6, best machine i have owned....get yourself a D2 coil and you have a depth monster that will keep up with all but the most expensive machines...BTW, both the m6 and the mxt share the same lineage, they were developed as additional product lines from one of White's gold machine models...i prefer the m6 becuase it gives you 7 tones whereas the mxt only gives 1...that said, if i lived somewhere that i could prospect for gold i would have opted for the mxt...the only thing i do not like about the m6 is its discrimination. to me they should have adopted a system that allows you to manually disc out targets based on vdi numbers instead of the sequencial knob that the machine has now....one last thing, the m6 and mxt use the sames coils as the dfx and vision...so if u upgrade later you will have all the coils you bought available for use on the new machine....
John