The .260 is better. I have both (Rem 700SA and 725SA, respectively). I've taken caribou, elk, and a wolf with the .260, 140 gr. Corelokts so far, and I love that thing. Carried it for moose the last 2 years, but they were uncooperative, until the day I carried the '06.
Over the years, I've taken caribou, black bear, Dall sheep and moose with the .243, using 100 gr. non-premium factory loads. No flies there - except on carcasses. Haven't run a round through it in 5 or 6 years, however. Might have to break down and hand load some of those premium 80-85 - tried that weight in plain-jane on caribou some 30 years ago and was less than satisfied, but bullet technology has taken a few steps since.
The .243 and .260 are both calibers that "kill better than they should" as someone else once put it.
