I've had three separate blowouts with these tires.
One was the rear tire during a technical descent (Mt. Baldy), thankfully it was a slower section, although it was strewn with rocks. After an inspection it was a vertical cut in the sidewall.
The second blowout was during a race (criterium). The damage was very similar to the above Specialized with Zipps (torn sidewall along bead). It was a pretty violent blowout (tire exploded and deflated almost instantly). The blowout was mostly caused by the fairly rough roads that the course was on. The potholes and cracks in the road that were deep enough to damage the sidewalls enough to weaken the sidewall.
The third blowout was similar to the first one (vertical cut), although this time was on straight flat city roads. Must have been the plentiful debris of metal and glass that are strewn all over bay area roads.
Needless to say I don't plan on purchasing anymore of these tires. Sure they have decent grip and are fairly supple for clinchers, but something must be said about the sidewall strength of these tires. I'm sticking with Vittoria from now on.