Konstantine reviews the top 3 selling kukri machetes. He rates them based upon the 4 criterias that makes up a great knife. His favorite criteria is how well the sheath is. A knife with a bad sheath is like a car with bad tires--it sucks.
In the article, Konstantine noted how machetes usually use soft metals instead of carbon steel because it is easier to sharpen in the field that way. Also, soft metals allow the knife to withstand more abuse.
For Kukri knives in general, Konstantine noted that you would want one that is not too large where it would be a hassle to carry around. You are looking for one that would be great on your hip during a hike. Also, small Kukris are just a novelty--do not buy it. You can read the full report here http://bestmachete.net/
Konstantine La lives in Boulder and is a veteran of the US Army. He knows a lot about knives and survival equipments.