I'm glad to see a thread about Marbles knives. I have several, and I really like them. They are great performers. I'm sure their heat treat isn't as good as 52100 treated by a Mastersmith, but it is pretty good nevertheless. The combination of fine grained 52100 steel and the full height convex grind results in a wickedly keen edge.
My wife will occasionally grab my Fieldcraft and use it in the kitchen.