Carville should not be working for CNN and John Kerry at the same time, that is a clear conflict of interest.
I don't think republicans fear Carville, but he is definitely respected as the best in the business along with Karl Rove as a political operative. Kerry should have made him the #1 guy in his campaign from day one if he was available. I personally admire the guy although I disagree with just about everything that comes out of his mouth. He is also quite entertaining.
Begala does not impress me but ditto on the conflict of interest.