They're both great rounds with more similarities than differences. I shoot the 260 and have been very happy with it. Would've been equally happy with the 6.5C for my purposes (mostly hunting).

At the range I've been hearing a few people talking about moving away from 6.5x47 and going back to the 260 because they were having to push the 47 really hard to match speeds with the larger case. Have you guys heard any of that?