PDK stands for Porsche Delight Killer. Sad but true: the German automaker’s engineered most of the fun out of it. Like ye olde Tiptronic, the PDK really likes to upshift. I started out normally from rest at an intersection. Before I reached the other side, PDK had shifted twice. By the time I reached 30 mph, I was in seventh; I felt like I was driving a Trabant with an aromatic leather interior. PDK behaves like a student project designed to extract maximum mpg from what used to be a high performance sports car.
Back when I drove the new BMW M3, I wondered why I needed all those shift modes. Now that I’ve driven PDK, I longed for a few of those shift modes. Porsche gives you one, otherwise, its paddle for yourself. To make matters worse, PDK is not particularly PDQ. Upshifts are not noticeable but downshifts are lurchy and slow, even when performed manually. On top of all this, the ergonomics of the steering wheel controls are awful. Again, upshifting feels OK. But downshifting requires that you almost reach behind the wheel for the change. Not to put too fine a point on it, PDK ruined my 911 experience.
Source: The Truth About Cars