After reading all those forums about how certain players swear by them and others hate them for dying quickly or eating their frets, I had to see for myself. I installed them on a Fender HW1 Precision Bass with a Dimarzio Model P pickup.
Feel:
Rougher than nickel-plated strings and DR stainless, but not annoyingly so. More noise while sliding. Very nice tension.
You can smack that low-E and it will stay nice and tight!, it really suited my style. The 43 gauge is also a pleasant surprise. It doesn't feel tiny and too soft like a 40 , but you can bend it easier than a 45.
Sound:
When new, it sounds almost like a grand piano, with great clarity all over the neck. The highs are bright but not unpleasant. I had many string sets that had that annoying high pitched fret click that stayed even after the string went dead. The mids are scooped but there is some unique high-mid content that cuts through, especially when you dig in or play with a pick.
The lows are nice and deep but not boomy. Also high up (above12th fret) on the E string.
Those strings really feel a little 'rude' and 'alive'. There is a certain sweetness to the overtones and string buzz that I enjoyed. The notes pop off the fretboard and the clarity while playing chords is impressive, even down low.
They DO NOT die off quickly, especially if you wipe them with a cloth after playing. I've had them on for 3 weeks now and they settled nicely, with a bit more mids and less presence and scratchiness. I also don't think they would wear down your frets quickly. Use proper fretting hand pressure, with any roundwound string.
In summary:
Great for 'in your face' bass tone.
That's the sound you've heard in so many records! Don't hesitate to try them. Different basses and gear will respond differently, but the liveliness and clarity will be there with these strings.