Things in favor of the 308:

Short Action
Inherent Accuracy
Broad Availability of Bullets (.308)
Works With A Remarkable Variety Of Powders
Miserly Powder Consumption
Works Well with Carbine Length Barrels
Staggering Amount Of Affordable Factory Ammo
World-Wide Military Use

Things in favor of the 270:

Jack O'Connor Used It

grin

Seriously, I like both and there is no "righter" answer...

“Perfection is Achieved Not When There Is Nothing More to Add, But When There Is Nothing Left to Take Away” Antoine de Saint-Exupery