No, I do not drink them at all.
But I am writing to let you know that a major cause of obesity is, amazingly, diet drinks. Most diet drinks contain aspartame, which is a poison that screws up your metabolism. Furthermore, with diet drinks, you don't even get the real satisfaction of old-fashioned sugar, so that causes you to eat even more.
Furthermore, if you are buying "big gulps", "super-sized" anything, you are a super idiot.
Hint: why not try REAL fruit juice? NOT fruit flavored beverages that outnumber the real juices in the juice aisle at the store. READ THE LABELS. Natural juice. No aspartame or other artificial sweeteners. No additional sugar. No "high-fructose" corn syrup.
Prove that you are not a typical idiot. Read the labels. No diet drinks or juices. Real juice only. Is it really that complicated?