I also have the 255/35WR-19's on the rear due to my car having staggered rim sizes standard.
So far, these tires have surpassed expectations. The current ratings (5/6/11) give the impression that these are substandard tires for the money. They most certainly aren't. My current ratings should show how I feel about them. Before these, I had a set of the much more expensive Michelin Pilot Sport A/S's and they, in my opinion, aren't worth half the money these tires are.
These tires inspire full driving confidence through high-speed, high-g corners. They are also excellent at highway speeds while running through heavy rain/a few inches of water. No hydroplaning to speak of. Responsiveness is excellent for an A/S. Ride comfort and noise levels are, for the most part, comfortable and quiet--comparable to the Michelins.
For now, I do not have a rating for any snow or ice traction as most of it was gone by the time I had these put on. These ratings, along with treadwear, will be updated later when they are applicable.