First off, make sure you try on some NB shoes before you order so you get the right size. NB shoes have odd sizes, i wear a full size larger in just about every other companies shoe.
It took about 4 days of wear to break in, it hurt my ankles near the end of the day until they broke in properly.
The sole is very grippy, the shoe is very light and very warm - indoors your feet may even overheat a bit.
I'm very happy with them, but they probably won't get much use when it gets warmer.