I don't like the blandness of water, if you want a first-person perspective. I consume a lot of diet soda, probably 8-10 cans a day. I'm always drinking something; if it's not soda, it's green tea, or gatorade, or coffee. I always need to be drinking something and diet soda is... well, something.

It's not much of a decision point, I don't really think about it in terms of expected value or return on my choice, diet soda is simply the answer to the question of, "What are you drinking?"

And despite articles like the submission, there's no real observed downside to this choice (I'm not obese, and have never been obese, so this article doesn't really apply to me), other than potentially what the carbonation could be doing to my teeth, and as long as my dentist doesn't seem to have any concerns (she doesn't), I persist.