While both shelters work well, I'd easily grab my DuoMid over my Stratospire 2 if I was expecting rough weather.
Also, in some situations the most storm worthy shelter can be the one you can set up quickest. When a storm rolls in and you need to bail off a ridge and camp, ease of setup can be just as important as theoretical ability. Single pole shelters tend to win this category, with fewer sides being faster than more sides. I'm surprised no one makes a 3 sided pyramid.

