Dave, Hunting here in the midwest, where I have moderately mineralized soil conditions, I have not noticed any significant difference in depth, between the X-50 and the X-70. However, I am very maticulous in setting my X-50 properly. By that I mean that I set my sensitivity fairly low, and ground balance my X-50 as close to "perfect" as I can. Then I raise the sensitivity level as high as I can, without causing it to chatter or false. Most of the areas I hunt, I can run "full bore" with the sensitivity on the X-50. With that said, I suppose it is reasonable to assume that you could adjust both the ground balance and the sensitivity to a higher degree of accuracy with the X-70. In my opinion, I don't believe that the X-70 is any more sensitive than the X-50, or that the there is any difference between the highest level and lowest level of ground balance between the two models. But, as I mentioned, the X-70 allows you to "fine tune" those levels more precisely than the X-50. You can adjust the X-70 sensitivity from 1 - 30, where as the X-50 only has 2/3 as many places to set it, running from 1 - 20. As well, the ground balance on the X-50 can be set at any level from 0 - 20. And the X-70 offers manual ground balance settings of 0 -99, as well as automatic ground balance, tracking and beach modes. So, even though the high end and the low end of each adjustment may be the same, the X-70 does allow you to chose a level that may more closely represent the level you need to be at, to best utilize the detector.
With all that said, I do like the X-70 for several reasons. I like to hunt with a slight threshold tone, allowing me to run in a Pattern and hear the "blanking" effect created with rejected targets. I like the capability of using any one of three frequencies of coils. I like to set my ground balance automatically, then tweak it manually to optimize the settings. I like the Prospecting mode for target sizing and additional pinpointing capabilities. None of these things make my X-70 hunt any deeper than my X-50. But they all add to the my enjoying the hunt! HH Randy
