I have the Kabar Eks (all three models), a Richmond Model 4, and an Effingham Model 3.
I can tell you the latter two look more "traditional", and they seem to "fill" a larger hand a bit better. The Kabars feel more streamlined, the blades are a bit slimmer and more utilitarian, and they seem to be the ones I would reach for for actual use. I also prefer the carbon steel in the Kabars.
They are arguably different knives. I like my Kabars a lot; but I would have to say that I am glad I have the other two; because they are more like I have always known the Eks to be, so I can say I have a "real Ek"; and I don't know if I would say that if I only had the Kabar Eks....if you know what I mean. But if I wanted a working Ek, I'd be happy with the Kabars.
I realize that's completely subjective; and I'm sorry. I really haven't put any of them to serious use, so I cannot be very technical. But since we are talking about Eks, I figured there would be a certain subjectivity to what you were asking.
From a purely "knife" point of view, the Kabars seem to be every bit as good a field knife as the blade design would dictate.
