So far no issues. Unexpectedly drove through a snowstorm last night (~5" fell, pretty heavy and slushy and then later compacted/icy) and felt confident throughout the drive(s).
Car didn't have any issues with either ABS or traction control. Only time I actually had to use the brake pedal (instead of just regen) I didn't have any issues.
During non-slushy/snowy conditions, the car feels and behaves just like with the summers, with a slight reduction in suctiony grip, of course. No errors or other warnings since the tires have been put on.