It's a shame John jumped to the conclusion that weight taken from the business end of a Pacerpole will require more energy in use. In fact, taking weight from the end of the pole reduces the energy needed to use the poles significantly. (The centre of gravity is nearer the pivot point [your hand], and the overall weight is reduced - result, a much lower moment of inertia).
Fastening some heavy weights to the end of your poles soon shows that more energy is needed to use them. It also shows that heavy ends are not as quick to respond or as accurate in positioning.
I've only used carbon Pacerpoles so can't judge the difference, whereas John has used Pacerploes for thousands of miles and is very able to judge the difference - he says he can't. But then, can you tell the difference between a 120g and a 100g stove when it's on your back? All these weight savings are marginal but all add up to the good. Poles are like boots, the weight saving has more effect than the weight alone would suggest.
John was right that they're quite long when closed down, and this could be a nuisance beyond any energy saving.