I had a Randall #18 for some years. The early ones (through the era of the American presence in Viet Nam) had the tang bent to one side inside the handle and silver soldered against the inside of the tube. Later ones have a two-inch or longer section of the handle that is left as a solid billet, with a fairly wide tang threaded into that. I've never heard of one failing, and I'm certain that if Randall had, they would have changed the design. There are many cheap imitations where this is a serious problem, but I would be amazed if it were a concern with either Randall or Reeve. They are both excellent products, and worthy of extreme trust.

That having been said, I eventually sold mine. It's weight and bulk, the roundness of it's handle (and it's symmetry, with an asymetrical blade.. though it is angled slightly, and that helps a bit), and the fact that the balance changed a lot depending on what was in the handle, finally started to bug me. I found as time went by that it was more and more seldom with me.

It's worth noting that on the Randall #18, the sawteeth on the back are explicitly NOT for wood, but for sawing out of the aluminum skin of a downed aircraft. The fact that the Chris Reeve knife is called the "aviator" makes me suspect that he may have had the same use in mind.

Both are very well-made knives, and in your position, I wouldn't worry a bit about durability, but I'd be more concerned with whether the weight, bulk and design is what I want for real use. Of course, no one can answer that for you- but both are almost legendary for being well made, durable knives. If I had to choose between them today, I'd go with the Reeve, mostly because the much-less-cumbersome guard should make it less of a pain to carry, but neither would be my first choice.