Mountain Dew and Dr. Pepper are both popular soda drinks with unique flavor profiles, so what one enjoys may not be the same for someone else.  Mountain Dew has a sweeter, citrus-like taste and contains more caffeine than Dr. Pepper.  On the other hand, Dr. Pepper has a distinctive taste that many people enjoy - some compare it to cola mixed with prunes or cherries - and its lower caffeine content can make it easier on the stomach for those sensitive to stimulants like caffeine.  Ultimately, both Mountain Dew and Dr. Pepper offer a great taste and provide an excellent addition to any refreshment lineup!  So it comes down to personal preference when deciding which one is better. Enjoy whichever drink you find most pleasing!