Getting back to the OP's question, SS barrels, I own all types.
Oly often substitutes SS for CM at no extra charge. And their M4 contour barrel is available only in SS last time I looked.
MOST of the accuracy of SS barrels is because they are generally bull barrel contours. SS is chosen for bull target barrels because it rifles nicely. But Oly is one of the few who make the more "normal" contours from SS. The difference in accuracy of barrels with similar contour, but SS, chromemoly (unlined) and chrome lined chromemoly all but disappears when you start shooting real rifles. There is just very little practical difference.
Durability? I have "rode hard and put away wet" SS barrels. In semiauto use, the barrel extension wears out before the bore does. I don't know how SS will do on full auto, but right now the local Sheriff's Office is trying its best to wear out one of my discarded SS barrels (20k+ rounds) on one of their M16's and not having much success.
Treat your SS barrel just as you would any other barrel.