@DebraDownSouth:
Which is why clicker trainers wipe the floor in competition with shock collar and those using any physical corrections, even citronella collars. It isn't that clickers are magic, it is that they build on training quick automatic responses which simply are neurologically "friendly" to training. (And no, I don't use a clicker much other than trick training, but I know many who use it for everything.)
Of course you are building automatic responses whichever method you use. An interesting statistic I gleaned from "Accelerated Learning" by Pam Reid is that dogs conditioned to a recall by means of a really nasty shock retained the training far longer than with any other method. Her comment was that after the training you could basically throw the collar away and never use it again. Investigation revealed that the response was continually reinforced by the relief the dog felt at evading the shock by responding to the recall, which supplied positive reinforcement every time the dog heard the cue. Timing is crucial to using this method, as is conditioning the dog to NOT associate the collar with the shock.
I have personally not used the collar in this way, but the fact is that positive punishment correctly applied is indeed extremely effective. The problem lies in the fact that most don't have the timing to do it accurately, and also that most of us don't want to cause severe pain to our animals, even when it is of very brief duration. Modern e collars can be used with less physical discomfort than an ordinary collar and leash, but give you the advantage of control at a distance. The cautionary is that they are not a good tool unless you spend the time to learn how to use them correctly, and I don't think they should be sold independently of a course in their use. I also think they are not appropriate for some breeds of dog as a stand alone training tool, but are valuable with dogs such as Basenjis to remind them that there are consequences to ignoring a command that they understand, and I have no qualms about using the collar in this way. My dog is fully aware that HE controls any discomfort he may experience.
BTW, as I have mentioned before, I agree that clicker training is an extremely effective way to teach new behaviours, and I use it myself all the time. However, I haven't noted any particular trend of clicker trainers predominating in the obedience ring, although they appear to have more of a following in agility. Not sure why this is, but it could be because of the "culture" of the different disciplines. 
Would love to hear your comment on "comfort zone". I used the term without particularly thinking about alternate interpretations. I know what mine is, and would like to know whether yours varies much from what I intended…..lots of meaning gets lost in translation. Especially on the internet.
