Porsche Design (pd) Eterna watches are very well made as you would expect. They use top quality movements and all of mine (past and present) have always been well within Chronometer ratings. The watches generally have little design nuances that make them that little bit different from normal run of the mill pieces.
The pd ethos is clearly important to carry through and you pay a premium for that at full retail (not that I suspect many people ever pay near that price though).
Pre-owned or NOS though the watches present a compelling argument and really do look special when on the wrist, at the right price you cannot go wrong. Here is my Porsche Diver watch that carried a rrp north of £12k.