If you are planning to use the rifle for just deer then i believe that the .270 is the better option for 2 reasons. 1. It is a classic deer cal., it has a very good flat trag. and more than enough hitting power.
2. If you decide to go after larger game such as elk or moose you will have the perfect excuse to purchase the .300.
It would be very logical to me. Plus, he who dies with the most toys wins.