So I just got to test drive a white e90 with DCT at Autobahn this last weekend. Had 17 miles on the clock when I hopped in.
Absolutely phenomenal! Just too bad it wasn't a demo car that had been broken in. I only ever hit like 5k RPM.
If anyone in the area wants to test drive a DCT though, I'd suggest going there and trying your smoothest line to get into the seat. (I don't think it was suppost to be test driven is why)