Yes! The 6906 is the evolution of the 669, so it is exactly what replaced the 669. You get the ambi safety (only some 669’s had them) and you get a much better rear sight in the Novak lo-mount. The front sight is also upgraded, a dovetailed modern sight and one that you can upgrade if you so choose.

Those are the obvious upgrades... less easy to spot are the ergonomic improvements. If you hold each pistol in your hands, you can see and feel where S&W made them fit your hands better and knocked off and rounded some sharp edges.

If the price is same or nearly the same, the 6906 is a much better value. As “collectibility” goes, it’s only about nostalgia, both models were made in volume and aren’t really much interest to collectors, although the 669 was made in shorter supply than it’s brother the 469.