its all preference. the .308 is a nice round, and yes you can get bigger bullets, but the .270 is a flatter round. yes the velocities are about the same, but it goes beyond that. the muzzle energy and down range energy are higher than the .308. just depends on what you are shooting, bullet, powder, etc.
Remington 710 .270
Smith And Wesson M&P40
Mossberg 835 Ulti-Mag 12 Ga
CVA optima Mag .50 cal. Muzzleloader
1968 Browning recurve