I like the idea of congestion pricing. If tolls are set such that a constant flow of traffic is maintained, roads will be more efficiently used and drivers will save time and money. My enthusiasm has been tempered by Becky Akers' article Congestion Pricing: The Road to the Surveillance State.
The potential to use congestion pricing as a mechanism to track motorists is a major concern. Likewise is the use of the tolls. Instead of being used to maintain or expand roads, the tolls are being used to subsidize mass transportation (buses and subways).
As good of an economic idea as congestion pricing is, if the political process skews it, no congestion pricing may be better than a deeply flawed one.