I guess a rigorous test might provide some interesting data. Seems a pity to destroy a work of art though. And of course that test would only prove what that particular blade was like. Every khuk could be a little different.
A khukuri designed for hammering, levering and heavy chopping might have a thicker blade and be tempered a little softer in the critical areas.
I will certainly vouch for the good quality and usefulness of the two H.I Khukuris that I own.
I must say though, that being a metalworker with a reasonable idea of what might cause breakage, I carefully rounded the edges and corners of the cho area with fine emery paper just to make it less likely that a crack would start there.
The cho makes the khukuri a khukuri I guess, but to me its location on the blade is somewhat unfortunate from a pure design point of view. It shouldn't be a problem for a khukuri that is tempered well and used in a reasonable manner. I see the cho problem as a similar situation to a variety of other knives where the sharpening ends abruptly...I feel that in some circumstances that this is where a crack is likely to start (but generally only when an extra stressful load is applied to the steel).
Axe and hammer handles can have a similar theory applied to them. You may have a really weak handle with a crack, or a knot, or a sudden change in size next to the head (ie...not a taper). All goes well while you let the weight of the axe/hammer head do the work, and while your aim is true. However, once you overshoot the wood you are trying to split, or when you use the tool as a lever...crack !! It's busted.
When chopping with a khuk, I think it is best to ensure that the weight of the blade is allowed to do the work, and that the blade hits the work at the well balanced 'sweet spot' on the edge.
Looking at my Ang Kholas, I reckon they'd simply have to endure more abuse than many knives of the same length.