I bought these strings to fit a PJ bass, looking for that smooth and deep thump.
I was surprised to find that they retain a mid rich snap that gives them a very unique tone, although not for everyone's ears. It is not a traditional PBass sound, even when you roll off the tone knob, and they definitely don't work for a J Bass sharp attack. They are also capable of producing a decent slap tone, although (again) not a very common one.
Also, you should keep in mind that they have fairly low tension and will easily produce that aggressive snap against the frets, which may or may not be to your liking.
They are definitely worth the try if you're into trying different tones, but if you're of a more conservative nature I would probably skip them and go for a traditional flatwound.
I believe they may be amazing on a fretless and I'll probably have to buy myself one just so I can try them.
Pros: A different tone if you like that sort of thing, very smooth on the hands and the frets
Cons: A different tone if you DON'T like that sort of thing