I'd much rather read articles that show the good and the bad sides of things like e-collars instead of pure "anti-shock collar" articles by the "positive only" extremists, but that's just me. Sometimes I think that "positive only" extremists go too far, spread misinformation and overplay the "pain, fear, and abuse" caused by these tools. Certainly, when used improperly, an e-collar can and will have those effects on a dog, but when used properly, I think they can be beneficial in some situations. As with training collars (another tool with a bad rap) and prongs, I think e-collars have their own place in a trainer's toolbox. I don't think an e-collar is not meant to be used as a harsh aversive in most occassions. When done right, I don't think these things are supposed to cause anxiety and fear in a dog. Reading through some of the articles, trainers who use the e-collar speak out against using these tools abusively. In the links to the articles I posted, I remember reading that the desired response is only an "ear flinch" or something of the sort -- any more than that and they tell you to lower the setting. And you certainly can't use them on just any dog.
I've read again and again that positive reinforcement works best; I especially enjoyed reading Karen Pryor's "Don't Shoot the Dog". However, I think that a particular tool shouldn't be instantly written off as inhumane and evil. Most dogs aren't made of glass, and using aversives (like leash pops) here and there won't spell the end of the world and the psychological destruction of the dog. I do not advocate using the e-collar for regular obedience training, but I do understand using it for proofing and for "last resort"-type situations. What if that's the only option left -- what if everything else has not worked? Better to take an educated chance with an e-collar than to dump the dog at a shelter.
Anyway, what do I know, I only train my dog with a clicker.