I replaced the original Aquila Nylgut on all my ukes w/ the Martin. The concert size Lanakai and the Cordoba definitely sound nicer w/ the Martin M600. Maybe a tad less volume than the Nylgut, but noticeably better clarity and sweetness. On the Lanakai tenor pineapple, due to the short scale length, the tension feels a little too light, so I'll be looking for a heavier gauge set.