since nobody has specified what "best" means, the implicit connotation is one's favorite dac, regardless of its sound.
in that case, the first zanden dac smokes them all.
Regardless of its sound? What else would it be a favorite on the basis of? Its looks, perhaps...construction? I kind of lost you there.
It is reasonable to assume the OP is asking for a personal favorite based upon experience. What qualifies as "best" obviously will differ from person to person depending upon their priorities. In this respect, the best one could hope to come away with is a general idea of what some people prefer, and use that as a point of departure. If one wanted to reference this further one might go back and look at the posting history and or ask questions of the person rendering the opinion, to further discover where their preferences might be similar or disimilar to their own. Your statement, "...the zanden smokes them all," implies that you've heard "them all" in direct comparison to the Zanden. In what respect does it "smoke them all"? And what "all" have you done direct comparisons with, having both DAC's in the same system in the same room, at the same time?