Future classic: Ford Falcon XR8 vs Ford Mustang

What do you think of the Falcon XR8 as a long-term keeper? I’ve often missed the boat with cars I should have bought going up in value and now I could buy this Falcon. My nephew works for an importer of new Mustangs and tells me to forget the XR8 and buy a Mustang. I’ve driven it, and it’s a fantastic V8. What do you think? And a Holden is not in the picture, as good as it may be.