PDK vs Manual...
1st time I drove a 991GT3 (with PDK) I thought it was amazing... but the car itself was amazing, and there was so much going on it was hard to comprehend the various elements of the experience. I'm sure most people would have their 30 minute 991 test drive (GTS or cooking 991 would be similar), come away feeling the same, and end up ordering a PDK.
However, after driving it more, and the novelty of the amazing engine, performance, handling, steering, etc had worn off, it became clear to me that for road driving at least, losing the physical action of changing gear made the car less interactive, and less enjoyable to drive. PDK is amazing when you're fully on it, but when driving more sensibly a manual is a much nicer tool... and with the level of performance all 991's have now you'll spend much more time at sensible speed than fully on it.
As a counter point...
Couple of weekends ago I had my 1st proper drive in my brother-in-laws DB11, which has an 8 speed auto. Full chat down narrow b roads, and a fast cruse on some A roads. In this car, an auto 'box makes much more sense... it's heavier than a GT3, slower in it's reactions, less of a sports car. I don't think a manual 'box would suit it at all.