I've used these for some training rides and 4 crits. About 500 miles. They roll really fast. In my normal training ride, rolling at 28 mph is the same effort as 25mph on standard rims, if not more. I have them set up with schwalbe R.1 tires and latex tubes, pressures ranging from 110-125psi. I weigh 160lbs.
The wheels do not ride very well compared to varous alloy rims that I have used (mavic, easton, sram), which is expected. But it's enough to experience a loss of control in some situations. The worst for me was a fast left-right transition in a crit where I hit some very bad rutts. Almost ripped the bars from my hands and caused me to lose the lead pack. I would avoid using these for decents on poor quality roads-the loss of confidence in the front end does not warrant the increase in speed.
Windy conditions can be a big issue. If the wind is steady then it's OK and controllable. Gusty conditions however can be down right nasty. I've been moved over about 10ft in a couple of situations.
Some of the terrain I've used these in has been pretty rough and both wheels are now noticably out of true. Removing the tires is required to access the nipples. For this reason, I would avoid the tubular version unless you are prepared to baby them.
Braking is marginal, I equate it to installing the cheapest hardest pads you can find, age them 5 years in the sun, and use them on your std alloys. My flat bar commutter with apex calipers and cheap alloy wheels has astoundingly better braking capability than my racer with red calipers and reynolds. Not really an issue for most racing imo, but relevant in training conditions and emergency stops. I've used swissstop yellows and the stock blue pads. Blues are better.
Overall the wheels are good, but have limited use. I'd stick to races with good terrain and weather, and the very last ride before a race. You can use them for everyday training, but it's not worth the hassle.
They make cool noises at high speeds too. Like tron.