there is a GCN video from July 2016 where Dan Lloyd compares the time to descend a 4K hill with and without using a dropper post (it has been retrofitted to a Canyon Ultimate). He averages 10 seconds faster (mean of 2) with the dropper post - over about a 4.5 min run…and then offers other comments on increased confidence and stability and predicts it will be coming to a grand tour soon.