For me, I the '06 gets the edge if I intend to hunt game where there is a legitimate need for bullets heavier than 140 grains. And it's not because you can't kill an elk or moose with a .270. In my experience, the perfect shot or situation doesn't always present itself in the real world so I like a little room for error. I'm not talking about rump shots either, just a little edge and the .30-06 has it on bigger game. On close in shots, it seems the '06 will render less meat blood shot and damaged on less than perfect hits-a real concern for some hunters east of the Mississippi. On critters the size of a large mule deer and on down, there's little if any difference in killing effectiveness between the two.
Just my thoughts.