Dogs that are operant seem to be happier. I clicker train all my dogs and I would not train them any other way.
When I teach a new behavior I like to start out by shaping. Shaping is an advanced form of clicker training and my dog has to be operant. That means, offering a new movement if I don't click and reward. That is why mixing clicker training and non reward markers (NRM) does not work well. Dogs will stop to become operant.
Once a behavior looks like the end product, I add a verbal cue while my dog is doing the behavior. Shortly after that is when I stop using the clicker and start using the verbal marker instead.
No more clicking needed, at that location with that behavior. Timing of the verbal cue is important and if it is being used to soon my dog does not know what behavior I am asking him to do. Once the behavior is on verbal cue I do not reward my dog for offering that behavior. That is were some trainers get confused and claim that clicker dogs can't do a long sit or long down.