Check this thread for a discussion on strings. There is lots said about the merits of Newtone and Elixir. There are plenty of thread, just put in Newtone or Elixir in the Mudcat search bar.

I use Elixir Nanoweb bronze on my guitar and phosphor bronze on my bouzouki (the PB have a slightly warmer tone). I used to use D'Addario but although they sounded lovely when put on, they went dead within a week. The cost of replacing these regularly is much less than the cost of Elixir which will retain a decent enough sound for several weeks, if not months. The Nanoweb has a thinner coating than the waxy feeling Polyweb and also retains some of that "string squeek". They can be obtained quite cheaply mail order but I like to go to the local music shops. I'm not reluctant to try Newtone, I just like the ease with which I can get Elixir.