I tried Prim strings because folk fiddler Garry Blakely uses them and his sound is magical. I found them a little difficult to get used to at first because the sound is so clean and distinct that every intonation error is immediately exposed. In contrast to, say, Zyex, or Helicore, there is no warm envelope round the sound - you have to create the warmth with the quality of your playing. On a good day I think I'm in heaven with these strings, but on a bad day, the opposite is true, so I find them challenging. Reliability is excellent - they stay in tune easily. Durability also excellent - they last and last with consistently good sound.
