Apple juice is definitely a tasty treat, and seeing that it's fruit derived likely has some good things associated with it. Often, it is fortified with vitamin C and has some other reported benefits, like boron for bones and antioxidants. However, some of these things (like boron and some antioxidants) haven't been definitively (scientifically, in peer-reviewed journals) shown to promote health, so that aspect of apple juice is debatable! Some unprocessed apple juices may actually have some fiber content, as well, depending on the method of production; however, most apple juice likely has little of this part of the apple (fiber/insoluble things makes the juice less clear, so lots of people try to keep it out).
One major downside, though, is the sugar content. Apple juice is extremely tasty for this reason! There is a ton of fructose in apple juice, and this is the same sugar that is used to flavor many sodas. You drink too much of it, and you'll have the same problems as if you drank too much soda! By the way, whether it's "natural" or "artifical"/"high fructose corn syrup" or whatever, fructose is fructose, so don't get thrown off by marketing tactics.
I hope that helps! I tried to make it as objective as possible based on what you can find online.
Health Benefits of Apple Juice
Apple juice is one of natures healthiest products. There are a lot of positive health benefits of apple juice and very few negatives. Its a good drink for both children and adults. It is even used to make some common alcoholic drinks. On top of all the benefits to your body, it is the most inexpensive fruit juice to produce on a whole.