I first heard Rotosounds in 1969. I was literally stunned at the sound and ring they had. I have now been using stainless rounds for decades, although I currently use mostly flats. I've tried them all, you name the set, I've probably tried it. Other than some of the newest brands like String Joy and Magma, DR, Dunlop, LaBells, Smith, GHS, all of 'em. My favorite stainless set, is the Ernie Ball Hybrid Slinky- and if I need a set for a 5 string, I buy a separate .125. The D'Addario Pro Steels are similar but come with a .130. Those two, are the most 'zingy' sounding, and longest lasting rounds there are. Great price usually, as well. I also use S.I.T. stainless, but those are not as bright. I stopped using RS66's in the mid seventies, when this poor working cover-band bassist got some dead strings brand new in the package! And in one case, an entire set.