The only real advantage one has over the other is that the 7mm-08 turned out to be so popular after its introduction in 1980 that the .260 never got off the ground.
As a result 7mm-08 ammo and brass are much more widely available, and 7mm-08 brass tends to be more consistent, due to ammo companies replacing their brass-forming dies more often.
If anybody in the 21st century wants to settle on one cartridge for everything from large varmints to elk, the .260 is the theoretical winner. But only rifle loonies have ever heard of the .260, and rifle loonies NEVER own one rifle.
