I have been using Argentina for my gypsy jazz guitars for almost 10 years, and so far are my favourite, it is true than they loose brightness in a week if you are practicing every day, but they don't loose tone and they give the right sound for gypsy jazz, I have tried other brands so far this is my favourite, actually in the last few years they have improved how much they last without loosing tone, I remember changing the strings every 2 months or even before that, now they last more than 3 months no problem