I normally use the Ernie Ball nickle round wound Hybrid Slinky set, gauges: 045-065-085-105, but am pondering on trying out a set of round wound Cobalt Hybrid Slinky with the same gauges. Now my question is, as the headline says, how they are compared to the nickle wound set?: Do they have about the same tension and stiffness? Do they have the same smooth feel? Do they really keep the freshness of tone longer as advertised? How are they tone wise?: The information on Ernie Balls homepage suggests that cobalts have slightly higher overall output, but also that while the nickle wounds have a pretty linear frequency response, the cobalts have slightly less mid response in comparison with the treble and bass response of the strings. And finally, are they in your opinion worth the extra money paid?