I bought the 335xi after my 1999 Volvo S80 T6 died after 300,000 miles. The engine, transmission, and drivetrain are more connected than any competitive model tested. The steering is precise and it a blast to drive. I still smile when I hear it's subtle exhaust note when I start it in the morning. The AWD system is very good in all conditions but the run flat tires are not designed for snow. They were OK in winter #1 but will invest in snows next fall. My biggest challenge has been reliability. They had to replace the front wheel bearings at 14K miles and I broke down at 17K miles and had to be towed to the dealership to replace the fuel pump and repair an oil pan leak. Not what I expected.
The twin turbo. Bluetooth is better than wife's Audi by a mile. I get comments about the clarity. Adaptive headlights are great and LED's on door handles is a nice touch. iDrive is great after the first couple days. It's easier than Audi's MMI in my opinion. Maintenance plan.
Reliability has been terrible so far on the car I got. Driver's cup holder is a joke but a small price to pay for the overall performance. After a New England winter hitting a pothole with the run flat tires is pretty rough.