Your decision may be influenced by the type of camping you enjoy.  For us, we will almost always stay in a State Park, National Forest, ACOE campground, or similar.  We Rarely stay at a resort or private campground.  Just our preference.
For us the 30' motorhome works great.  It limits the amount of stuff we haul around (a blessing, just do the essentials), it is easy to drive,  Lots of power for the 18,000 lb weight, I can get into just about any campsite that is somewhat level for a 30' distance, and we can use the insides without extending the slides.  The floorplan of the Winnebago Sightseer 29R was perfect for our lifestyle....too bad this floorplan is so hard to find.  The perfect RV for us would be a "30R" with the extra space in the bathroom/shower area.