430 stainless is going to have both edge retention and corrosion issues limiting useful life - be very careful with it in the salt.
The titanium MMC edge is limited by wear and its thickness, but how much real cutting do you do with a neck knife?
Something else, both the neck knife and fillet knife won't cut your finger unless you try. It's edge is not achieved by sharpening, but by normal use-wear.
If you've ever used an abrasive cut-off wheel, it's the same idea - all the hardness and cutting edges are in the micrscopic second-phase particles and the matrix wears away to expose more.
I used to carry this Matsuda hand-folded Damascus, Nickel+VG-10, both razor edge and salt-impervious,
but realized if I dropped it in the bay, would never be able to replace it.
here's my freshwater neck-knife/nipper
I have Swiss Army knives, too, but only use them for the great cigar cutter