In reply to Indy:
Never used them ,but told they can be horrible in the wind.
If I used Zipp 808s or 404s in my neck of the woods ,I would be off the bike.simples.
I've been blown sideways across the road ,and felt the bike being blown from under me ,using standard rim Mavics.Puts the wind right up you.
Not for windy days.and windy days are few and far between on a bike