The truth is, either one will do nicely. If elk or heavier game is a possibility, then the .270 is the better choice. If it's gonna be pretty much just a deer/antelope gun, then the .25-06 is a fine choice.
The best thing is, this is a win/win situation! No matter which one is chosen, it will work just fine, as would a .243, 257 Bob, .260, 7x57, or whatever.