Over the years I have used a variety of strings. Recently, I put on a set of their new Cobalt strings on my electric. They were noticeably better than the strings which were not very worn, that I was replacing on my guitar. They actually lived up to their advertised features (More output, better harmonics and great feel). I have only had them on for about 2 weeks so they have not been fully vetted but so far I would have to say Excellent.