Two great calibers. As you probably know, they use the same case. With the bullets we have today either caliber is a top choice. If its mainly deer then the hands down choice IMO is the 270. Last season I shot nine Mule deer with nine shots from the 270 with 130 grain Federal Fusions. They went nowhere after being hit. I would not hesitate one second to hunt anything but the biggest bears (grizzly and polar), with the 270 and the right bullet. The 30-06 will do everything the 270 will do but the 270 will shoot a bit flatter and kick a little less using 130 grain bullets. As RH said, the 6.5x55, 7mm-08 and 7x57 will do the same job.