You know what? I'm going to reserve my judgment until I've driven one. Plain and simple.
I buy BMW not because of the toys, or even the quality of the dash materials; I am on my third BMW car now because of driving dynamics. Yes, the other stuff feeds into the perception of the car, but for me 95% of the car is how it feels when I change gears, push the throttle and turn the steering wheel into a sweeping turn.
I won't discount GM; they've built some damned good cars. Back in 1999 I had a brand new Pontiac Grand Prix GTP (my first ever brand new car). Talk about horrible interior materials; but that engine was seriously to die for and just the addition of a strut tower brace completely changed the feel of that thing's steering in the corners. A smaller supercharger pulley and some minor engine mods and the thing was a seriously smoking-fast car. From a driving dynamics perspective it only fell behind because it was front wheel drive. Later versions of the same car never quite had the same feel. I only got rid of it because my new and newly pregnant wife hated the hard ride and the rather unyielding leather.
2001 E46 BMW 330i Sport Package 6MT
2004 BMW R1150GS
2004 E60 BMW 545i Sport 6MT
2012 BMW 135i - Deep Sea Blue / Terracotta / DCT
2012 BMW K1600GT - Vermillion Red Metallic
2008 BMW E90 M3 - Interlagos Blue / Silver / 6MT