These strings are advertised as having a "BRIGHT" tone but that's really just for a couple of hours. Depending on how you look at it they either go dead very fast or they are extremely dark sounding for a roundwound. They have a really nice "dead" sound though. They're not muddy at all and even though they're dark they still have a nice focused attack. The best word I can think of to describe the tone is "dry".
There's a rumour on a certain online bass forum that these are actually the same strings as the more expensive Rotosound Nickel 66 (the ones in the blue packaging) just without the silk. That's simply not true. The Nickel 66s sound different and last much longer before they do dead/dark. I actually got this confirmed by Rotosound, they are NOT the same strings.
These Rotobass strings are only suitable for people looking for a dead/dark roundwound tone. If you're looking for a bright tone you would have to change these strings at least once a week.
Still, I like these strings better than most of the other cheapo nickle plated sets like D'Daddario and Fender but then I like a somewhat dark roundwound tone. I like to have at least one bass strung with worn, mellow roundwounds and the Rotobass sets are great for this.
Recommended as a decent allround nickle plated roundwound on a budget but only if you are looking for a dark/dead sound. If you want brightness you're better of spending a bit more on higher quality strings. It will be cheaper than replacing these every week.
It's difficult for me to rate these strings because personally I actually like their "dead" tone. But they're advertised as "BRIGHT" and in that regard they're a total failure and I guess they should be rated as such.