I think there are different degrees of nylon/steel. I find Silver Slaps quite nice to play and they also sound rootsy/gutsy, but I briefly used a set of black nylons - possibly Rotosound although I'm not sure - that both felt and sounded quite plastic, not something that would be a problem so much on electric bass but I really didn't like on uptight. They may have improved with some playing-in, but I decided against it.
The problem with all of this of course is that you might love the type of strings I don't