I like 'em tone-wise, and the tone lasts for a long time, but they do seem to break easier than the D'Addarios I usually use. And they're getting more expensive, altho JustStrings.com has a fairly good price on them at the moment.

( http://www.juststrings.com )

I've been told by different people that D'Addario sells Elixir the strings, then Elixir then adds the polymer to them...anyone have any idea if this is true?