What would be considered an advantage or disadvantage will differ for each person. Some people think the distance from campus creates a sense of peace and quiet. Some people will be unwilling to make longer walks to class. Some people will enjoy more spacious digs. Some people will hate the cleaning and upkeep that's required.
The biggest advantages of living off-campus are branching out on your own and starting to gather up some experiences you can learn from, both good and bad. You're managing your own place and your own budget, cooking your own food, fixing (some) of you broken things and dealing with your own landlord. All of those could be seen as advantages or disadvantages, depending on the person.
With the right outlook, there are basically no disadvantages to any college living situation. Other than bad roommates. Bad roommates are the worst everywhere.