Sorry for not responding on PM. I was in Italy for a cycling trip... Back to your questions - I have put some miles on Zipp 404 and Corima Aero S, so hopefully I can give you some feedback.
Aero + and 'S' - The hub is the main difference. 'S' hub is oversized, bearings are bigger and should be more durable. Otherwise the wheels are the same.
They feel stiff and responsive, but not harsh. It's hard to rub the breaks. The hubs are butter smooth and easy to service. The breaking is actualy quite good, great modulation, no pulsation. There are rims/pads offering higher top end stopping power, but the difference isn't that big.
ZIpp 404 is a great rim, but Corima is much easier to live with - better handling in crosswind, hubs are troublefree and much stiffer. If you prefer silent wheels, you will be happy with them - they hardly make a sound. The Zipps are probably faster in straigh line, but I would take Aero S every day.
If you need more info, just ask