The M is a fabulous car to drive. The engine, with its lightweight internals, has to be one of the best Ferrari units ever made. It revs more freely than a TR and was a key part in my decision to buy one. Not many Ms were made (501) so it's hard for people to experience and give informed opinions. The Countach does look super cool. I like Horacio Pagani's styling, though the original is prettier, the anniversario has panache. It would be a real head turner. It's just a bit too extroverted for me, but that's subjective. I think the Countach will be a better investment but who knows.