From the owner of a 16 foot Airstream: single axle is one less set of tires, brakes, and axle to replace. Smaller is shorter and shorter is harder to back up. Take that as fact from prior owner of 35 ft mh, 35ft 5th wheel, 25ft Airstream and now the 16ft. Easier to pull and maneuver. Less fuel required to pull. Less expensive tow vehicle to own. No sway in our case. What you have now may well be paid for.
We really like our 16ft. It is what we need now. We recently used it to go to Boston from South Louisiana. Very easy to hitch and go. We just use sway control but no weight distribution bars.
