I will agree that the "Guinand" name does not carry any goodwill or value, at least here in the United States. The name is difficult to pronounce; the heritage is unknown, at least here in the US; people who do know the name may associate it with stopwatches, which are not especially valuable. Perhaps Helmut Sinn's adoption of the Guinand name is like Carroll Shelby being involved with Oldsmobile or the "kit cars" / replicas later in his career . . . not the same heritage or collectibility as the Fords, but there may still be some "keepers" for those who admire his work.
To me, the appeal of this watch is largely in its use and display of the beautifully finished (legendary) movement. Make no mistake, I do like the rest of the watch . . . but I am buying the old 427 Ford engine (or maybe the 289), which Shelby / Sinn is now mounting in a nice looking body.
Jeff