I also use Elixir Nanoweb Phosphor Bronze .012-.053 gauge on all my steel-strung guitars, and have done for many years. There was, I believe a bad patch in the firm's history - perhaps around 2 years ago and before that - when 3rds and sometimes 4ths broke regularly.

My opinion, and that of other guitarists I talked to at the time, was that the ratio between the inner core and the outer winding was wrong - inner too thin to support the outer winding. I took it up with Elixir (the European office in Germany), giving them evidence of the guitars I used, styles I played, etc. - together with some comments culled from around the web. I got a very efficient reply - and two free sets of strings - but naturally they wouldn't admit directly to any design flaw but promised to investigate.

I'm sure that my efforts on their own didn't amount to a hill of beans, but I do think that many other guitarists also contacted Elixir with their opinions. Certainly, in the last two years - no change in guitars or playing styles - I haven't broken a single Elixir string and I'm sure they've changed the spec.

They are the only strings that don't give way to the acid in my hands. Martin strings last me a day's playing and then their dull. I do prefer a very bright sound.