Just for the record, I have played both of these strings. I used the Cobalts (45-100 set) about a year ago. I liked the sound a lot, but gave up on them after a month or two because I found them still too "grabby" and rough-feeling. I have had the Dunlops (45-105) on my bass (a humble Squier Jazz) for about a month now and distinctly prefer them. If, as Michael said above, Sadowsky Black Labels are about halfway between classic Labellas and the Cobalts, I would say that the Dunlops are about halfway between the Sadowskys and Cobalts.
Sound: Dunlops have a bit more brightness and dynamic range than Sadowskys, IME, but a bit less "growl" and more "smooth"-sounding than the Cobalts. They work fine in my current hard rock band, allowing quite a range of tones, from Labella-like thump with tone rolled off to quite bright, almost Cobalt-like spank with the tone full on. Overall, I would describe the sound as "smoothly punchy" for flats, more versatile and more "musical" sounding than other alternatives, like Chromes and Fenders. Also pretty well balanced as they break in. G string is still a bit brighter after a month, but not impossibly so, and E is not too woofy.
Tension/stiffness: The Dunlops look and feel distinctly more like traditional flatwounds. I would say they are slightly stiffer and slightly higher tension than the equivalent Cobalts, but nothing too extreme.
Touch: Dunlops are very much smoother to the touch than Cobalts. Not not quite the glassy slickness of Labellas or Sadowskys, but much closer to that than to the relatively rough-feeling Cobalts.
In sum, I would recommend these strings for anyone who wants some of the punch and dynamics of the Cobalts but also wants a bit more of the smooth feel of Labellas and Sadowskys. Hope this helps.
