S125V can be chippy at high hardness and thin edges. The Fantoni was at around rc 62 and not where I'd consider too high, nor was it too thin. I don't know about the Ferrum Forge knife though. It is VERY wear resistant and has a very high carbide fraction so it will never be tough like some of the tougher stainless steels, example Elmax, S30V, S35Vn, etc, much less the very tough carbon and alloy steels like 3V, A2, etc. Not in the same class or anywhere near. More like ingot 440C tough which isn't up to the modern powder stainless steels.
Keep the angle at 35degrees or more, don't make it too thin , and make sure it gets a good heat treat and temper(s) and it will do fine especially with a 3-400 grit sharpening.
I prefer A11 class ( 10V/K294, etc.) as it's about as wear resistant and much less chippy at higher hardness's. Look at the results on rope Jim Ankerson gets with that class steel. It's nothing short of wonderful performance wise and capable of much better geometries.
Joe