I apologize to anyone whole owns or likes Cayenne's for what I'm about to say, but IMHO the Cayenne looks like a 911 experiment that went horribly bad. It's one of those things that I thought was sort of unimpressive when I first saw it, but as time passes I really, really don't like it.
In fairness, some people have complained about the X6 styling. But I think the X6 and its M sibling have unique style characteristics that grow on you, and you appreciate them more and more as time goes by. That's to say I liked it when I first saw it and even more so today.
Get the X6 M.
BTW, it's fast,
too!