I have Blizzak LM-60 on my '11.
I wanted to stay with the factory tire size, so I had to get a Performance Snow Tire. The Blizzak WS-60 (or 70) are a better pure snow tire, but the wear is not as good. Also sounded like the WS's weren't as good in wet. Around here, they keep the roads salted pretty good, so most winter driving is in the wet. Plus the transition in and out of the winter months is raining.
Yes, Blizzak's are more $ than most, but I did a lot of reading. Plus I figured if I'm going to drop a bunch of money on wheels and tires, I'd spend the little more and get what I felt was the best. On other Mustang site's Blizzak was one of favs.
If they are in your size, I have heard the Firestone WinterForce were good, but I have no experience with them.