The D'Addario strings, to which you refer, are called Nanowebs. GHS has also come out with a coated string, called EXP's, and considered to be several cuts above, both the Elixirs and D'Addario Nanowebs.

Coated strings seem to work best for those whose hands sweat profusely or whose acidity is high. In addition, pickers who play several hours a day say they last longer than uncoated strings.

I've tried Elixirs twice and I absolutely do not like them. My personal preference for strings is Martin SP Phosphor Bronze. A flatpicker friend equates Elixirs to strings with a condom.