[quote="tobygfoster"]... the Zipp marketing ... guarantees this won't happen... quote]
Zipp is clearly a winner for marketing. But you know nothing guarantees some bad luck will happen with any part of your bike. Manufacturers certainly are aware of the major issues with brakes tracks we have heard of on full carbon clinchers. most manufacturers say they solved the problem.
If you're concerned about the reliability of the brake track, go with alu brake track, either on a FFWD F4R, or older 303. They're about 100g heavier than full carbon.
If you want the best low weight/performance wheels available, IMHO, get either the tubular version of the Zipps or the F4R.
I know in europe the FFWD tubulars are pretty cheap (With Taiwan hubs. With DT Swiss 180 they must be pretty pricey)
I use the FFWD F6R tubular, and tried some older 404's and also the Firecrest version. I can't see or feel the difference between these brands. On paper the Zipps are lighter.