I bought these for a fretless Ibanez SRF700 Portamento.
As it has a very sensitive, microphonic Piezo element in the bridge, it picks up a lot of string noise. The "soft" nylonwound external of the string provides a smooth, slick playing surface, and the steel core provides a lot of clarify!
I play a lot of harmonics, and if you crank open the bridge pickup and the piezo, it really sings as a fretless should.
The neck-through construction of the bass is good for sustain, and makes up for the slightly shorter sustain of the strings. They do not lack in sustain for fretted guitars, and bolt-on necks, but for a fretless you sometimes go into "ambient" stuff, and then you need clear, long sustain.
On a fretless you don't get a lot of wear on the strings, but on a fretted bass I suspect the lifetime of the strings will be a lot less, due to the softer windings.
They're also a lot kinder on your fretboard than steel/nickel strings (even if they're flatwound!).
These are a very strong competition for the LaBella nylons.
Give them a try!
