Often asked question that boils down to what really matters to you. If you are thinking of going with a 5er, make sure that tow vehicle can handle the payload as many larger units will require a 350/3500 dually to do the job satisfactorily. The reasons given for their choices between the two types of trailers are personal as both have their pros and cons depending on the poster's viewpoint. Recent year models of 5ers and TTs are becoming quite similar in layout and design that virtually whatever one desires to have in their rig is available in both formats. Go with what feels best for your particular situation and enjoy your new rig.