I vote open, car hauler (preferably aluminum) or 8.5' wide enclosed, with any kind of V-nose for aero, they pull so much nicer in shit weather.
Not a fan of the flat front sail, like PJ's.
That's a ~20' Kaufmann Tilit-Deck car hauler, that we added removable sides to.
v-nose, flat, still gonna get horseshit mpg no matter so im indifferent there, although it does seem that most trailers 7x14 ish are v-nose fronts.
i still keep going back to the little trailer to save on weight and try to keep the frontal area low
although parking my sxs inside an enclosed trailer would be pretty sweet.... alllllthough id need to go 8' wide for ease in/out at that point