Superb sound. New users may be confused by the ratings regarding tension. Red Card is 'normal' in most people's understanding and Yellow Card is high tension. THey are all a fraction higher tension than other brands but it's hardly noticeable to ordinary users. However, my tutor really enjoys the smoothness and response of the Yellow Card. I think the only way to tell is try each on your guitar because it's clear to me that every guitar responds differently, in addition to the player's preference. All these strings are superb in tone and quality - although I wish that all string makers would offer a few more centimetres of length on top strings in case of trouble.