I've owned a pair for 5+ years. Stopped by the Hed factory and spoke to personnel for detailed information, and bought a set shortly afterward. The Hed tech recommended the RC6s vs the RC4s for overall speed, and they still are very controllable in crosswinds. My speeds increase when I ride this set of wheels. They handle great with the wider rims and corresponding wider tires (25mm usually). I love the stopping power of the rims-I use SwissStop BXP pads. People comment on the sound they make during riding, and also the turbine sound when stopping. Highly recommend.
These are excellent. With Swiss stop pads great breaking. Ride awesome. Best of all worlds. I use for training and triathlon. Would buy again above all others regardless of price