KMC is a fine chain company. Their products will serve you well and last as long as any other. Unless you have Campy components and want the status of having a Campy chain, go for the KMC. If you race and pay for your own equipment, go for the KMC or any other chain that will most likely get you through the race. It'll be better to have 2 chains that are less expensive than one very expensive chain. It won't matter the brand because in racing any chain will be beat to Sh** in no time and the Campy chain will just cost you more.
Also remember that it doesn't matter that your chain says Campy when you're shouldering your bike down the course because your RD just shattered.