Of the three, I like the fighter the best. Now thst it is offered in a straight edge, I think it improves on the classic kabar in a lot of ways.
That said, for field use, I dunno if I would pick any of those three. They all will work just fine, but I dont think I would baton and pry with them too much. Kabars and their copies are "tough" but not really "robust". By that I mean that they are "tough" inasmuchas you can throw one under a jeep, bend the tang to hell, and then straighten it back over your knee and roll on. "Robust" is more a function (to me) of being able to be pried on, slammed, and twisted while maintaining its shape. The Becker would be better for that. I am kind of digging my new TOPS Combat in that role, but it is pretty dang heavy if weight is a factor.
Any of the three you listed should be fine if you use them within their parameters.