I caught that article last month - it was an excellent read, very eye opening. More importantly, because they tested every tire class in a controlled environment - the results actually mean something.
The M3's are fantastic as long as you are driving in a straight line. They have more than enough get up and go traction.
My issue with them (as you pointed out as well) is the cornering capabilities - it's miserable. No winter tire should make me feel scared on a highway bend with a slight dusting of snow. I've found myself having to take 90 degree corners at slower speeds than surrounding traffic at times.
Definitely my last pair of "Winter Performance" and Dunlop is going to have to bend over backwards to get my dollar anytime soon.