Hiya,
The things about modern snow tires that make them so good are:
low temperature compound -- they stay soft in colder weather
the "snicks" in the tread blocks open up when the tire is under rotational torque:
http://www.tirerack.com/tires/BigPic...tnum=865TR5XI2
...which provides much more surface area to grip the snow and ice. The zigzags in the "snicks" act to lock the tread blocks together, so they do not lose dry pavement turning grip.
These Michelin X-Ice tires have a sidewall maximum pressure of 51PSI, and they have lower rolling resistance than my Yokohama "summer" tires. They grip very well in ice and snow -- I drive through almost anything; uphill, in deep snow, on wet ice, you name it.
I like a standard shift in the snow, for the control of tire spin and torque, and the ease of gently downshifting. Though an automatic with full stability and traction control, and full snows, I think this combo would be unstoppable.