My uncle once owned a 911 for a few years. The life of the car quickly went downhill after a quick drive through downtown Charleston, SC, which left his car turning left at a light while his right front wheel took off for the straight path. I guess the joints weren't the strongest, but it was amusing to watch the tire go a good 30 feet on its own. After that it was one maintenance headache after another - I don't remember him ever having it out of the shop more than a few months at a time before he unloaded it.
All that said, they're beautiful beasts.