At least in the States the F75 sells at $934USD & the X70 for $699USD with two coils. As far as Coin/Relic machines they are in two different market segments in the U.S., high vs mid-range. The X70 as well as the other X-Machines are marketed as All Arounders, while the marketing materials for the F75 aim more at the Coin/Relic, with emphasis by the majority of users on Relic. Whereas the X70 has a dedicated Prospecting & Saltwater capability.
The parent company FT faced a bit of dilemma positioning product. The top of their Bounty Hunter line sells for $450USD, then when they decided to enter the higher portion of the market under the Teknetics brand they positioned the T2 at $799USD, almost double the cost of the BH at $450USD. With the acquisition of Fisher, what appears to have been the successor to the T2 was branded as a new Fisher. The question remained of where to position it in order to not kill T2 sales, which would leave many unhappy dealers.
Then there's the aspect of the complexity of the testing, which coils of the X70, what type of detecting, relic, coin, prospecting, saltwater beach. When the X-Terra's first came out there were a few coils available, but now, the test matrix table becomes very large. What type of ground conditions, and who does the various testing, I wouldn't want to square off against BT or Steve Herschbach under any circumstances using any combination of machines in the gold fields. So is it fair to take a new machine F75, with users that have very little time with it, no dedicated Prospecting mode, and send them into the gold fields with BT plus his X70 in hand? I think the only thing you'll learn from such an exercise is that BT knows his X70 very well, and knows how to find gold very well. But we already know that!
HH
BarnacleBill