I had the old style 575, although a veritile bike it was too flexy for harder descending duties, not sure on the new model though.
The good thing about the 575 is that you can build it into lightweight XC bike or something burlier.
however if the remedy is your second choice, then I think the Yeti will struggle to compete with it in “burly and stifness stakes”
Have you considered a Lapierre Spicy? truly awsome machines, probably not the plushest suspension but out accelerates even lightweight XC machines and the geometry is spot on for descending…the perfect do it all machine.