Hi, I am going to be buying a new carbon deep section wheelset for my bike and am stuck for choice between two wheelsets. I can get both of them for exactly the same price so that is not an issue. I am deciding between the Zipp 404 wheelset and the Shimano 7850-50 50mm wheelset, both in tubular. Do any of you have experiences with these wheels? The Zipps weigh in at 1250g a pair and the shimanos at 1469. What I would really like to know is if one wheelset is significantly more aero or stiffer. Most of the racing I do is on flat rolling courses. What wheelset would I be best to get?