Its pricey, like all other fast tubies, but it also handles the rough chipseal roads of the Saltaire Time Trial as well as it handles Colorado Springs' velodrome. I have it mounted on my Sub 9 disc and use it for both track and road. Great tire!
Just like the Grand Prix's in the clinchers, I converted over to tubulars this past summer. Picked up a pair of Zipp 303's and the Grand Prix's. I don't pretend to be a bike wrench, so my LBS installed these tires and they took a week to apply these tubulars properly. They also installed Orange sealant in them. I couldn't be more happier with this setup. Not sure if its the carbon layup of the wheels and the Conti's, but the ride on this combination is great.
The parts of San Diego that we ride in have some of the nastiest roads with pot holes, etc. I try to avoid these, but some of the roads I've ridden in, the wheel and tire combination have not let me down.
I do carry a can of Vittoria Pit Stop and a spare CO2 just in case. Also, the sealant has caused some issues with the removable valve core. There was an incident when trying to pump up the rear tire, the presta valve would not seal correctly (still letting air out). I jiggled the valve pin around to make it stop, but I took it into my LBS and they removed the valve core and replaced it with another one (no charge!). They told me the sealant causes these issues with the core and gunk's it up sometimes. The front valves seem to be fine. Stan's does make a valve core remover and I might get one and try this myself if this ever happens again.
They are a bit pricey, but so far so good.