I lived off Code Red one summer when I was marooned at JFK for 2 months opening a new terminal and it was the only Pepsi product I could stomach. Somehow I managed to go cold turkey when I got back home to my Dr. Pepper.
Smoking was far easier for me to give up than soda. I honestly found the biggest barrier to quitting was that I didn't want to quit, the 15 or so times I tried and failed I was quitting for other people or reasons I didn't believe in. If I could muster up the same anti-soda sentiment I did for cigs, no problem, I just don't see that happening.