I believe the Prindle 16 has less sail area, which could facilitate singlehanding.
It was mostly the lower overall weight and the fact that it is a little easier to right.
The difference in sail area is about 1 sq. mtr. in the mainsail (11 sq. ft) and a 0.5 sq. mtr in the jib (5 sq.ft.)
The boat as a whole goes better upwind then a H16 while the H16 goes better downwind. But none of the differences are to big though.