I've been using these strings for a lot of years now and I like them a lot. The only problem is I find they seem to lose their "zing" rather quickly. They seem a little too bright when brand new, and after being worn in a bit they get to a good spot, but it seems to not last very long before becoming rather dead. I don't mind it too much since among bass strings they're on the cheap side, so replacing them a little more often isn't a big deal. I remember I tried some type of DR strings a couple years ago that seemed similar to the RS66's. I don't remember if they were nickel or stainless, as it might have been during the time I was using the nickel RS66s before going back to the SS ones. I also don't recall if they actually lasted longer or not, just that they sounded good. I think I might just have to suck it up and try out some different ones trying to find something better. Or just stick with what I've been using, and maybe try using string cleaners and things to lengthen the life a little bit!