I had the Proxes 4 last year. They did a great job in Chicago area snow and slop. If you're going to run one tire year-round, Proxes 4 are a very good choice.
On the other hand, I didn't plan on changing over to Winter tires until this Saturday. We got hammered with our first snow on Thursday night/Friday. Needless to say, my T1Rs earned the term "Summer Tire".