What are advantages and disadvantages of travel trailers

In order to decide what to get, you first have to decide how and where you want to go.
If your planned usage is RV parks, be they State parks, COE, or commercial, then most any tt or 5er is fine.
If your desire is to go find someplace with no one in sight most of the time, your needs change.
Size of your family, summer or 4 season use, how long you intend to stay on a given trip, as well as budget all come into play.