The latest auction price (house "S") for a 5102G (aka "CELESTIAL") is about 356k USD..... In the same auction, a 5074Y (minute repeater + perpetual) is only 387k USD... just 30k more....
It is a more complicated and functional timepiece. The Celestial is beautiful, but it retails for about $190,000 which is far under the value of a 3974. Also, the 3974 is no longer in production.
my vote is for the 5102 WG.. the current production piece is now YG, and I think that the WG is beautiful based on the photos. The YG didn't look as nice. Plus, it's a special watch by PP, with the closest cousin to be the Sky moon Tourbillon which is really out of reach for most people.