I had these on my Nordstrand 5-string jazz bass for a few months as I was looking for strings with a warmer, more upright-like sound for jazz playing.
The tone of these strings is pleasant - they have more clarity than flatwound sets but don't have the harsh top end of roundwounds. They also don't deteriorate in the same way that roundwounds do due to the nylon coating.
The problem for me was the feel of the strings - the tension is lower than roundwound or flatwound sets that I've used before, and the strings feel oddly 'spongey' to play. I also found that the G-string sometimes slipped off the fretboard when I played higher up the neck, which has never happened with any other strings. Intonation on the B-string was not consistent, either.