I have a set of Kysyrium ES' (poor cousin to R-Sys!) and totally agree about the un-aeroness (yes, I just made that word up!) of the Mavic wheels with bladed spokes. I bought a set of Dura Ace C24s instead and find they are much better (a bit heavier than R-Sys but lighter than Kysyrium ES). I recently broke a front spoke on my DA front wheel so have had to temporarily replace the wheel with my now spare Mavic Kysyrium ES while I'm waiting for LBS to get spoke and find it quite dangerous riding in crosswinds, have literally nearly got blown off the bike several times in the past few days.