Fit and finish are great and in some cases superior to Swiss, as others have pointed out. Value retention depends on market, luck (whether anyone wants to admit it or not, c'mon, who bought a Daytona in 1940 expecting it to pay for their kid or grandkid's college career?), the model, and a lot of individual variables. It's less of a niche brand outside the states/N.A. in my experience - they've been available in the U.S. for a far shorter time, but in other places get the same polite nod of 'knowing' you might get from another watch nerd who notices a vintage Tudor Ranger or a newer Glashutte Original, etc. That's my experience, anyway.
Their more baseline models often remind me of Aqua Terra designs (moreso the older designs, to be fair), personally I'd feel equally comfortable with either for most situations.
*My own collection no longer includes a GS, but does have several modern divers and one vintage Seiko 7006, a newer Seiko 5, and hopefully a GS again soon.