Searching in no motion all metals mode is best suited to cache locating in places where digging a hole a foot deep won't get you thrown in jail or crossed up with a buried utility line. Plus in no motion mode searching, you're often having to fight signal drift. And, you'll have to keep on top of ground balance, no problem in some areas and difficult in others.
Major upgrades in the $200-300 range from the same engineers and factory that created the BH PEX include the Fisher F2, the Teknetics Delta, and the BH Platinum. The BH Platinum includes computer-assisted ground balanced no motion all metals operation, a feature which as far as I know is not offered by any other manufacturer in this price range, you've usually gotta go at least $500-700 for that.
--Dave J.