I have TIJFs on all my basses ... except my fretless jazz. I'd have them on the fretless, too, if only the A string were tolerable on this particular bass. Didn't like the LaBella LTFs on that bass, and after a lot of experimentation, I've decided the Sadowsky Blue Label Flats (current version) are the best choice. They're a bit stiff for me but I've lowered the action enough to make that work. Well-balanced, good feel, with plenty of mwah if you want it.
The other strings I've tried a lot on the fretless are tapes. The various LaBella whites are good if you want a near-roundwound vibe, while I've found the Pyramid tapes to be best for more of an upright vibe.
The other strings I've tried a lot on the fretless are tapes. The various LaBella whites are good if you want a near-roundwound vibe, while I've found the Pyramid tapes to be best for more of an upright vibe.