I find Open Pro ceramic rims fine, provided they are used with the dura-ace "ceramic" brake blocks. My audax wheels are 32h Schmidt dynohub at the front, 36h XT hub at the back, on Open Pro ceramics.
Its odd, coz there seems to be a real split in thoughts regarding these ceramic rims, while some people really rate them others hate them with affection.
When I had the bike built it was fitted with specific the Shimano "ceramic" blocks and in the dry and on long descents I was well impressed.
However, my first wet weather Audax event highlighted to me, anyway, another fearful side to braking characteristics. Once wet, and I mean really wet I had just about zero braking???
To the point where on a rather steep descent I was forced to take both feet from the pedals and dragging both shoes on the tarmac in a vain attempt to shrug of some speed.
I then tried lightly sanding the rims with the proper Mavic sanding block, in case the rims were polished, no better?
I then upped the game a little and moved to some course wet 'n dry, and still no better?
Then tried several different makes of brake blocks, Swissstop, Kool Stop etc. Then different compounds, but it was only throwing good money after bad, so they just had to go in the end.
I understand that Mavic have since stopped doing them now haven't they?