The biggest issue I have with aero rims is the harsh ride. Those 40mm+ deep section hoops are really stiff. Combine that with low-count, high-tension spokes and high pressure narrow tires, and you're in for a butt-hammer of a ride.
The aero benefit provided isn't worth the fatigue it causes (IMO) through transferring every little road vibration to your hands and behind.
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"I feel like my world was classier before I found cyclocross."
- Mandi M.