Durability wise I think Dynastar is far superior. Every Rossi ski I hear of breaks. A friend has broken 3 Squads, 2 RC112, and 2 S6s. Why he sticks with Rossi, I don't know. I went 40 feet to rock on my Dynastar XXLs and took out about two inches of edge and part of the sidewall. Considering the crash, I'm amazed they didn't just snap in half.
And to the comment claiming that all Dynastar skis suck, the XXL is my favorite ski ever. So stable, so durable, so fun.