For deer, there just isn't a better rifle than the 270. It shoots flat and fast and like you say the ammo is available everywhere. The selection of bullet is not a factor as the 270 will drop any animal in NA with a quality 130 grain bullet. All three are near perfect for deer hunting. However, to me the 30-06 is just plain more than I will ever need for deer hunting. My main gun anymore for deer is the 7MM-08 but I reload so ammo is not an issue.
If you get the 270, buy some 130 grain Federal Fusion ammo and you have it made in the shade.
