I've used Elixir for years now. Like others I didn't like Polywebs, but I use Nanoweb Phosphor Bronze all the time now. I've used all the standard sets from extra light through medium as I've experimented with differnt tunings and pitch. I sometimes tune up 3 semitones using exra lights with with a replacement plain third as the wound just won't take the higher pitch.

I should say that I'm almost exclusively a finger picker so I should be easy on the strings, but the only time they break on me is after I've been switching between tunings. If you leave them alone, just keep them in tune, they are indestructable, but if you continualy raise and lower (or vice versa) the pitch to alter tunings the repetition of relaxing and tightening the tension in the string is bound to induce metal fatigue, so eventually they breaks. The only ones which ever break are the 1st and 3rd, as they are the finest and therefore most susceptible. The wound third actually has the finest core, so that's why it's always the easiest to break.

They sound great and last for months!