So here's an update after 9,500 miles or so. The tires performed well all winter, handling rain and snow as well as can be expected of an all season tire. They remained responsive, good handling, quiet and smooth, and I was happy with them until returning from a 900 mile trip. On the way home they developed a high speed vibration which was not cured by rotation and rebalance. In fact, the rebalance only found 2 tires out of balance by 0.25 oz! Finally, a road force balance by my Audi dealer found both right side tires were out of round.
The rotation/rebalance was routine, but the road force balance/diagnosis was expensive ($130). The really important fact is that TireRack and Yokahama stood behind the tires. Maggie at TireRack was exceptionally helpful and 2 replacement tires were provided without charge. How good is that?!
There seems to have been some change in the tires, as now they take a set when standing in cold weather, reminiscent of the old nylon tires. After a few miles they smooth out. I think this must be just the replacement tires, as it didn't happen before.
If the tires hold up and don't go out of round again I recommend them highly. And TireRack is exceptional - no reason to buy form any one else.