All else being equal, I would prefer a single longer piece. But let's face it, 14 m is about 50 feet. How many situations are there where you are going to need a piece longer than that, and in how many of those will it be critical to have a single long piece (rather than two pieces tied together?

Weighing the ease of carrying two fairly long pieces against the very limited inconvenience of not having a single very long piece, I would recommend carrying two pieces, not one.

I'm open to being convinced otherwise, though :-)