Levi (a baldy) was powering up the hills at the ToC wearing a Prolight. So was Dave Z, but he's not bald.
Anyway, the Prolight always seemed cheap to me. It looks like the Giro Transfer, which is one of their cheap helmets.
With that said, I'd go with the Ionos or the S-Works if you've got the extra cash. The weight savings isn't that big of a difference.