Well for two of us. One person PillO hasn't been around in a good while. Both of us experienced the same problem. It wasn't roughness so much as our fingers would begin to be sore or ache after playing for a while. He is a pharmacist and all around sharp guy and concluded it was due to an allergic reaction with our make up and something in the strings. The Cobalt, I believe it was. He did also find that the gaps felt like little "cheese graters." Hence the Princess Fingers Club and our mascot in the pic above.