Chain,
It would depend on what loads shoot well in the rifle; in general, there is not a dramatic difference between them. My personal choice would be the .260 with 140 grain Bergers. That would compare closely with the 7-08 loaded with the 162 grain A-Max, but it should have a slight advantage in trajectory and windage. JMHO
Dave
Sounds like a couple of winners; 260/140s at ~2800, 7-08/162s at ~2700?
For the purposes of great brass, Lapua makes 260 brass and that is something to consider.
That said, I think I'd opt for the 7-08 with a 150 bullet.