What evidence is there that a MF loses depth in MF mode?
What do you mean by a MF machine will be 'noisier'?
I'm looking at getting a MF detector, currently have the Nokta Simplex but don't like it as there is too much chatter even with low sensitivity and ground balance.
The MF machines I'm looking at are the Minelab Vanquish 540, Minelab Equinox 600 or 800, or the new Garrett Ace Apex. There is unclear information about what frequencies they use then in multi-frequency mode, and what difference it makes. The Apex doesn't have 40khz for example.