There are not any nutritional benefits in drinking your common sodas, whether diet or not, in fact, the drinking of soda is hands down not good for your health and never has been. The basic problems with drinking soda are the fact that soda contains way too much sugar or sugar equivalent or sugar substitutes of which sugar in all of its various forms and flavors is debilitating to the body over time, especially in regards to weight gain, diabetes, and wreaking havoc on proper insulin production. In addition, to sugar, phosphoric acid is commonly added to sodas to give the necessary "bite" to the taste- buds as well as reducing bacterial counts for good shelf life, however, phosphoric acid is not good for your teeth enamel, your bones, or your kidneys, and sustain use of such is typically detrimental to your body.
There are plenty of people that like to drink juice, of all sorts, whether that is orange juice, or apple juice, or various other fruit juices, because they somewhat wrongly believe that fruit juices are beneficial for your body. Unfortunately, commercially soldfruit juices in most cases, are of dubious benefit, and can be quite harmful in the ways that soda is, by the simple fact that the sugar content in your typical juices is at the equivalency of soda drinks or sometimes even higher. While it is indeed true that fruit in all of its many forms is good for the body, the main reasons for this being so is the fact that fruit is filled with essential vitamins, antioxidants, fiber, as well as the sugar which gives fruit its distinctive pleasant taste. However, when eating whole fruit, you are consuming the fiber of the fruit at the same time with the natural fruit sugar, which means not only will this send signals to your brain that the fruit that is being consumed is filling your stomach up, it also means that the sugar contained within that fruit is being processed by your liver at a consistent and non-elevated rate that you are able to absorb it without any ill effects upon your body.
In addition, because of the way fruit juices are processed, packaged and sold, there is the misperception that you are getting all of the nutrients either naturally or added in that makes juice sort of like a liquid alternative to going through the trouble of eating the fruit itself. The fact is, that the lack of fiber as well as the removing of vitamins and other nutrients and the then adding in of flavors and other ingredients to give fruit juices a long shelf life and consistent tasting product is not the same as squeezing the fruit itself or eating of the fruit. In short, drinking commercial juice, no matter its label, is typically far different and not the equivalent to eating of fruit, and the fact that many people believe that drinking fruit juice is de facto good for you, is unfortunate and mostly wrong.
To make matters even worse, or perhaps ironic, the biggest fruit juices in the world, such as Minute maid and Tropicana, are owned by Coca Cola and Pepsi Cola, respectively, which means that with so much money in play and the liquid refreshment market at stake, they won't willingly cede ground to anyone or anything, unless they are getting a good piece of the action.