I have never ever seen a person buy a Porsche, because he is a snobby idiot. All I have seen and known, bought it for the fun of it.
It's true, though, that with owning a Porsche the whole world secretly envies you and therefore begrudges you owning one.
You don't have that problem with Ferrari or Lamborghini or Aston Martin, because those are simply too rare and exclusive for such a negative perception and also take profit from their "aura of imperfection", so to speak.
It speaks for the cars Porsche makes, that in spite of the bad image they still sell like sliced bread (compared to other sports cars in that price area).
I must admit, I'm dreaming about owning a lot of cars. But when I have an attack of soberness and rationality, I always have to admit to myself that I would rather spend my money on a 911, than on a Gallardo, a 430 or a V8 Vantage.
I have no idea how the Panamera will sell. But design is definitely not the issue. Otherwise the Cayenne wouldn't sell either (which I believe is not as ugly as opinion maker Clarkson has convinced Top Gear fans to believe). Instead it has become very profitable for Porsche.
I don't see the market yet for a 4-door-4-seater sports car. That kind of cars has rarely sold well. But if one company can change that, then in my opinion it's Porsche.