I have two helmets, a Giro and an Specialized (sorry - don't know models). I trade them back and forth all the time. The Specialized has reflective stickers on it and it's my dark/stormy commuter helmet. The Giro is noticeably lighter and seems to have less of a mushroom-head effect when I wear it, I almost forget it is on. The Specialized is heavier and I am a lot more aware of it while it's on my head (I think it may ride higher on my head so I feel it more, but I have no way of proving this). Both are comfortable and well ventilated, so to me the main difference is the weight and how aware of the helmet I am.