Ive had a set on my P bass for a little over a week now, the initial harsh high's and "new flat" sound is starting to going away. Here is my assessment so far:
Volume evenness: Really solid and even response across all the strings, better than most at this stage.
Tone evenness: Initially the E was huge, boomy and dark, while the other strings were "new flats" sounding. They are breaking in from the E down, E is getting tighter, A sounds identical to E now, D &G are just a touch brighter/twangier but are nearly there. I think a few more weeks ought to do it.
Overall tone: Its still a bit early, but they remind me a bit of the OLD Fender flats, but with more character and not as stiff. As they age the brittle "new flat" highs are softening, low mids are coming out and the bottom is tightening but still huge. You can get big round blossoming notes or that "digging in" P-bass grind. The tension is there, but they feel a bit more flexible and not as stiff as others.
Ill do an update again after they are fully broken in, but so far they are my new fav.