I was advised years ago to add cranberry to my diet by a physician. I have chronic congenital edema, and it made sense for my specific needs.
Generally speaking the first thing I do with any packaged product is to take it off the shelf, turn it over, and read the ingredients. At the time ‘diet’ cranberry juice was not available, and what was available was filled with corn syrup. So I bought straight cranberry juice from the health food store, and mixed it with seltzer or water or iced tea. It was strong and definitely NOT sweet.
Would I personally have bought diet if it were available? Well, this was back in the early 80s, so I might have. Of course, my mother loved margarine, but at that time they didn’t have the research on hydrogenated fat. I think research now is pretty good that the artificial ‘diet’ sweeteners do not really help with weight loss. And instead of retraining ourselves to enjoy food that is naturally sweet, or sour, or whatever, we are trying to feed our sweet craving without the caloric cost.
Most fitness professionals will (as you can see from your answers) suggest whole, fresh, and unprocessed, nutritionally dense food over processed, chemical filled food.
But if you are asking not a general question, but a specific question about you consuming this juice, that is a conversation that it would be really great for you to have with a nutritionist and/or your physician. They would understand your own specific needs and help you to make the best decision on this topic for you.