I like the steel in my machetes a bit harder than you commonly find. The blades in machetes are so broad that the only durability concern is the edge (assuming you don't go overboard with the hardness). My old favorite machetes were the Legitimus Collins brand (not related to Blackie Collins) that closed down US operations about 35 years ago. They were the top brand all over the Americas due to their toughness and edge holding. A soft edge easily ripples if you sharpen it to a narrow profile like I like to do. I never had a problem with edge chipping, just some denting. You can still get something similar to the Legitimus Collins models under the Nicholson or Nicholson-Collins brand made in South America. I have used Columbian models that were quite good.
I don't recall quite where I got my information, but I believe that the Collins alloy is/was a rather simple carbon steel, closer to 1084 than to 1045. They picked an alloy that would get hard and yet was easy for them to heat treat en mass. Legitimus Collins machetes could be distinguished by the way that they would ring if you flicked them with your fingernail. I think this related to how they were fabbed and hardened as well as the alloy. I would estimate that they were in the mid fifties RC. I would sharpen mine with a file and the file wouldn't skate, but it was definitely harder than the low 50s. I might guess it was in the 54-56 RC range. Anyway, I would not pick a stainless alloy for a machete.
Machete designs fall into two camps, thick and thin. A true machete in the South American tradition is thin and long. They are for cutting light flexible brush. When you are cutting brush, vines, bushes, and thin branches you need a fast moving thin blade that cuts all the way through your target with minimum resistance. Since your target flexes away from your cut when under pressure, you need speed to take advantage of the inertia of the target. A long thin blade moves fast and has minimum drag. The thick machetes are more of a Malay Archipelago tradition (Philippines, Indonesia, Malasia). In those areas there are more hardwoods to cut. A Philippine bolo machete is shorter and thicker (or at least thicker) than a Mexican machete. The thick US military machetes from early in the 20th century were devised for work in the Philippines. With thicker and harder wood to cut you want a blade that is similar to an axe blade in cross-section. When you cut into thick wood your blade tends to bind and be hard to pull out. A thin flat machete can really get stuck. A convex contoured thicker bolo blade can be more easily levered out. Thin machetes are optimum when they can cut all the way through or nearly through their target in one swing.
