This review does not actually pertain to the 3/4 Solo's I just bought, it pertains to the 3 sets of Spiro's I bought earlier, in '83 and '84. All are still doing well, and I did not buy the new set as a replacement, just for another instrument.
In my mind Spiro's are the ultimate jazz strings, and arco they do well too, but require precise bowing. Beyond that, their character is described sufficiently elsewhere.
If after 10 years or so they get darker because of dirt, grime & BLO, you can take them off & wipe them clean with a rag & solvent, and they are back to the perfect 1 year old string. So while I originally thought they were very expensive (then about the same as now, but back then that was quite a lot), they are actually very cost-effective strings.