I have not bought it yet.
I am actually trying one now.
A friend lent it to me.
First impression is: Very light and comfy, the visor protects well when the chin-piece is up, holds air pretty well when closed.
Defect: the chin-piece feels very light and I'm not sure if it would hold even in minor impacts (possible cause of injury?). The chin-piece is closed and locked by means of two automatic buttons so structurally is not very solid when closed.
In essence it turns out that the main reason reason why I like this helmet (the "rotating" chin-piece) is also the reason why I'm not so sure about it.