I recently picked up an Arione Open. I've been riding Ariones for 15 years, and this is the first open version I've purchased. (Needed a new saddle and my shop offered me a great deal on it. Figured, might as well give it a shot.)
Anyway, I like it. I don't really notice a difference between it and the non-open versions on my other bikes, in terms of comfort. I can say I no longer get saddle sores when riding the bike with the open saddle, but I attribute that change to the fact that the old saddle was just worn out.