Used a Niak this year for my first sheep hunt. Endured some serious wind, rain, and light snow in it, and it handles it like a champ. Used it on a goat hunt and it paid for itself the second night weathering a heck of a rain/sleet storm. During the storm while goat hunting, I shared it with my brother, a little cramped but it could have been worse. My brother made the comment about being impressed at how well it handled the weather.
I am sold on it being the best compromise as far as the weight vs durability debate goes. I'd also not have any worries about using it during the winter as well.