I just went through the same thing - at 27,000 miles of very spirited driving and some tracking of the car, the RE-050A's were shot, and slippery even when dry (not like racing slicks), my 60 ft times were climbing, not getting better. They were downright frightening to drive anywhere in cold weather - like bananna peels.
I did the same research and almost chose the Conti you are considering. I concluded that an all season would be my choice too, given that even here in the Deep South, we do get some cold weather and the Bridgestones were turning hard as a rock at any temp below about 45 degrees.
You've probably already been here:
http://www.tirerack.com/tires/tests/testDisplay.jsp?ttid=119
I was not able to find a good source for the Contis and had good experience in the past on other cars with Pirelli tires. There is a Pirelli dealer here that's been around for decades so, I know I have someone local to turn to if there are problems.
So, I went with the P Zero Nero A/S in the stock tire size. The Conti's may be a bit better according to some of the individual comparison charts at the above site, (wet performance of the Conti's when driven aggressively was very impressive) although the Pirelli edged out the Conti overall. Depends on what factors are most important to the individual driver. If you are still undecided or if the price differential is too much, depending on your source, I can tell you that I was surprised at the performance of the Zero Nero's so far, especially in the wet, even on warm days, and the Conti's may be even better.
I'm prepared to lose a tenth in the quarter in exchange for the cold and wet weather performance for my daily driver. I don't run the car on autocross or road racing, so I'm not concerned about giving up some performance there.
If I hear of anyone running the new Conti's I'll pass along their point of view. Should be a very good tire. Ultra High Performance All Season Tires have come a long way toward closing the gap with summer only performance tires, IMHO.