If your looking simply at a rarity factor, then the 5070P would take that category.
However, sorry no offense to existing 5070P owners, but I find the 5970 a more beautfiful watch.
I love chronographs, have owned several, but when in doubt, I tend to go for aethestics and additional complications.
So, no surprise, the 5970G would be my pick....hands down.
Good luck.
Arthur.