Distillation is a tricky subject. The bottom line is purity versus flavor. The more a whisky is distilled, the more heavy components will be removed. Certainly, one could argue that Armagnac is far superior to Cognac, though Armagnac is only once distilled and Cognac twice distilled. This is where the skill of the distiller comes into play.
It is important to capture many of the "good" components such as acetyl aldehydes, esters and others, while removing heavier fusel oils and proteins, which contribute to body and mouthfeel, but not to aromatics or fore-palate. As mentioned, Armagnac seems to do this quite well. While containing as much as 2500 ppm congeners, there is a good balance between purity and flavor as well as plenty of delicate aromatics and just enough body/mouthfeel creating proteins and fusel oils.
In Scotch, one could easily argue that some of the older Auchentoshans are exemplary, while many double-distilled spirits are mediocre. So, in essence, the skill of the distiller dictates the "goodness" of the malt. This question is akin to "Which is better, Roquefort or Chevre-lait?" Both triple distilled and double distilled malts have superb examples within their categories and the situation dictates which is better. I find during the warm summer months, a nice, light Auchentoshan suits my palate much better than some heavier highlands. Though, during the cooler fall months, its lightness doesn't provide the substance I am looking for.