I have all 3 variations.
I've been out of the loop for a few months so I'm not up to date on whats becoming scarce.....but needless to say they will all become sought after at some point, simply because Wenger knives is no more. From a collecting point of view then the set of 3 makes the most sense. I know that many members initially didn't like the titanium's. But that's a moot point these days.
I think the titanium's, like the 3 Business tools are what set Wenger apart from Victorinox, it shows how radical they were in their ideas.
As time goes by and new collectors emerge mint examples will be hard to find.