Getting moving is absolutely no problem. Turning can get hairy on occasion. One time (I'll never forget) I was taking a friend out for lunch, made a right turn at an intersection at a normal speed, not trying anything stupid at 20mph. There was a small "strip" of slush in the corner leftover in between the tire tracks, no ice. Once the rear wheels hit that pile of slush I spun out and did a 180. Luckily no one was around and it was a 2 lane road. Accelerating/turning moderately out of intersections with snow or slush will cause the rear end to trip up a bit and DSC to flash.

Oddly enough all of this happens in normal driving and part throttle. When I really try to kick the tail out for fun and hit the throttle decently hard, xDrive manages to do its thing with the differential braking and everything's semi-okay. Maybe I should just drive harder..............