When Cesar's methods "work", they do so because they are punishments and punishments suppress behaviors. Cesar seeks to mask the offending behavior; true animal behaviorists seek to eliminate the cause of the offending behavior. That pretty much sums up the argument.

There was an excellent summation of the difference between CM and +R people regarding teaching a dog to ignore an object.

Option 1: Give the dog's leash a snap or other aversive everytime it sniffs the inappropriate object.
Option 2: Teach the dog "leave it" using +R methods.

So what it really boils down to is...would you rather teach your dog by setting him up to fail or setting him up to succeed?