I drove a STEP 135 loaner for about a week while my wife's 6MT e90 was in the shop. It got me to seriously considering the DCT on my 1, but tonight I picked her car up and that's the end of that idea.
I have no doubt that the DCT (and even the STEP) can shift faster and more accurately than I can, but they don't shift like I want them to. It's silly and probably irrational, but as Xylarax said it's personal preference.
Oh, and her 328 is unbelievably tame after driving the 135 so consistently. She won;t like me having another reason to not like her car....
-dave