I do not like the one piece as it is no where near as smooth as the 2-piece. This is due to the resonant frequency of the long one piece DS being in the band that can be reached by normal driving. This is why Nissan gave the Z the 2 piece from the factory. The smaller lengths have much higher resonant frequencies which you could never reach.
Thus a lightweight 2-piece driveshaft would be optimal.
Follow Ups
Does anyone make a lightweight OEM style 2-piece driveshaft? - RonZ300 (Socal)14:27:53 05/26/12