[Seacidal]

I use a Spetton Mako, in large part because I like the flat profile. It has a great edge and resists corrosion. The rubber "keeper" at the top of the sheath works, but the knife's handle shape/design could be changed slightly to make it more effective.
It's a great knife for spearfishing and dispatching fish. Also cuts line effectively when needed, with both serrated and standard blade edges. Has a great sheath with quality straps.
Good luck in your decision.