Replying to IPhone?

I am really tempted to get one of these because they are so sick. I have enough to buy one if I want. My only question is, what is the durability like? I've heard it's super sensitive to moisture and is really delicate? Is this true? I will be skiing with it because I don't want to change phones every time I ski, so is it durable enough to ski with? I won't be dropping it in the snow or anything but moisture wise and stuff. Also if someone one here has one that is unlocked let me know, I may just buy it!