Pepsi reminds me of my year of slinging bread for Subway and Coke is what Mom would treat us with for mowing the lawn so either are ok I s'pose, but when it comes down to it Ruby Red Squirt is my carbonated beverage of choice.
Both are a carbonated (weak acid) acid. Way to start osteoporosis prematurely. It takes 1 gallon of water to undo what one carbonated drink does to your body.