I played unlined fretless for a number of years and always used rounds (Rotosound Swing no less). I found them far more zingy and dynamic.
I just don't get the current flatwound trend, especially on fretted basses. Hey ho, that's just me.
Okay...
So I bought a new Sire jazz bass about a year or so after they were released to rave reviews. Sadly I was disappointed with the QC.
Amongst other minor quibbles more prominent issues included one of the inlays sitting proud of the fingerboard by several millimetres (and at at a quirky angle); a faulty input jack; a preamp which failed after several days.
In my experience they were overhyped.