In reply to Em66:
I'm climbing with the black sirocco for about 1 1/2 years now, it replaced my Petzl Elios.
I never climb outside without a helmet (not wearing one affects my climbing. I could probably get used to it, but why would I).
Can't say I noticed any problems climbing in the sun. Compared to the Elios it's so much lighter and the ventilation is great.
I haven't used a white one though. If you compared it side to side maybe there's a noticeable difference.