i think 12 is hollow, 16 is not.
The 12 is less round, knubbier; perhaps easier to grip in hand for ground man while rigging, pulling your self up etc., harder for friction hitch to slide. i remember a long time ago, a local dealer calling the 16 strands 'fast lines'; and recomended trainees use 12 strand.
The 16 construction, is 'rounder' as a stop sign is trounder than a square, so i think the friction hitch rides smoother IMLHO
i think Samson ArboPlex and Wall ArboPlus have the polyolefin(sp.?) fibers that are hamburger helper filler fibers that are brittle, more heat sensitive and get 'raggedy' slowing things down even more in a 12 strand.
True Blue and Tree ProRed, are stronger, softer lines from same manufacturers respectively without the pololefin. So ithink those stuffer fibers give the line the lower strength artificially, but hits the diameter requirement
i always thought that True Blue lasted a long time, a premium 12 strand if ya want such a line.
The Blue Streak family is prolly the winner here; but i would never discount any of the NE Safety Blues, i think in time Yellow Jacket will prove itself more and more.