If you buy used, DEFINITELY hire an inspector. Our first rv looked great, no sign of any problems ( to our inexperienced eyes) inside or out. Later, when addressing a different problem we found significant wood rot in the wall framing in the bedroom slide and front corner of the 5th wheel.
Regardless of new or used I would recommend an EMS to protect against bad campground power. We didn't at first and it cost us over $2K in damaged electronics, ie: TV, stereo, converter, etc. We have a Progressive Dynamics hardwired unit, but there are other options. As others have said, it depends on what lifestyle you expect. For us, having TV and good cell signal are important. We have satellite TV and a signal booster for our cell service and MIFI through two different providers to be sure we, usually, have a good signal.