Jerry, I have two identical soprano ukes, both being the "Flight" travel model (one in orange and one in black). One is strung with Martin M-600's and the other with Fremont Blackline Hard Tensions. Both are tuned to the common gCEA tuning. Feel-wise, the Blacklines seem a little more "taut" and provide just a little more resistance when played, whereas the M-600's, by comparison, offer slightly less resistance and thus may be a little easier on the fingers. Sound-wise, the Blacklines seem a little bit mellower, whereas the M-600's offer a distinctive "edge" to the tone, which I find desirable. But, both sound very nice in their own way. The difference isn't huge, but it's discernible. And by the way, I don't mean to sound like a commercial for the Flight folks, but that little travel soprano (TUS-35), at around $60.00, is astoundingly good, and the tone it gives you, to my ear, doesn't sound "plastic-y" at all, even though the composition is primarily plastic (the soundboard is wood). The build quality is very neat and precise and consistent, and it features both a compensated saddle and a zero fret (which allows the nut to serve more as a "spacer" for the strings than as the actual "point of contact" for the strings; in other words, concerns about the precision of the depth and angle of the nut slots are pretty much eliminated with the presence of the zero fret).