I drove MT's for the 1st 20 years, then AT's for the next 20 years. After driving MT's as rentals during 3 trips to Europe and loving it, I decided to go back to MT's. So my last 2 cars have been MT's.
I like driving MT's much better because I am more involved and have more control of my car. And I never stop trying to perfect my shifts. And the MT should last longer. And it sounds better than a 328i AT I had as a loaner. I heard something besides the engine when I revved it - probably the torque converter?
If I was to buy an M3 or 335is, I would seriously consider a DCT. I'd drive the DCT back to back with the 6MT and make my decision. My main concern about the DCT is that is it more expensive, more complicated and new, which might mean more repairs down the road. I plan on keeping my car for many years.