I'm a believer in a good shock collar (yes, let's call it what it is!) used judiciously, especially for recall and boundary conditioning. We have 35+ acres, much of it wooded, and my dog has a very high prey drive and a mind of his own. He learns quickly, and is responsive 98% of the time. The other 2% of the time is a problem not easily rectified by other means. The 2% consists of either THE CHASE or THE EXPLORATION or both. Both behaviors are related to the prey drive, and both behaviors are EXTREMELY self-rewarding. My GSD loves us and we love him, but nothing I have to offer as reward can compete with the thrill of THE CHASE or the joy of THE EXPLORATION. And he knows that outside and off-lead, I cannot enforce my command. He is in the driver's seat, and he knows it!
I'm sure that if I spent hours and hours of training the dog, I could probably get it licked. But, I don't have hours and hours to spend, and in the meantime, the behaviors prohibit our having fun off-leash in the wide open area near the house. We live in the city, and when he bolts, he's off into the woods or the neighborhood. He always comes back, but he could get hit by a car, hurt in some other way, or just plain freak people out, even though he's not aggressive.
Enter THE COLLAR, a Tri-Tronics Pro-100 G3 EXP. DOG already has basic obedience, and the come command is well-reinforced off-lead in controlled settings and outside in the fenced-in area, and on a long light lead outside of the fence. However, once DOG had taste of THE CHASE and THE EXPLORATION, he's like a crack addict. Long story short, THE CHASE and THE EXPLORATION are no longer fun. In fact, SOMETHING BAD is out there now! Much nicer to stay close to Papa! SOMETHING BAD goes away when DOG close to Papa. SOMETHING BAD in the brush in the ravine! Now DOG finds no fun in THE CHASE and THE EXPLORATION. Now DOG has fun off-leash with Papa, playing and running and stuff! Now DOG can have fun going to explore with Papa off-leash, and SOMETHING BAD is not there!
This is the one area that I believe the e-collar excels in, and it can restore the JOY of having fun with your dog off-leash in the open.
As an aside, I did once try using the collar without really understanding it. All I succeeded in doing was to freak the dog out and freak myself out wondering if I'd screwed us both up for life. Thankfully, we both recovered quickly, and put the collar aside for a few months, worked on other training, then revisited the collar after having learned more about training theory. Once I understood what made the dog tick, applying the collar made much more sense, and it had VERY quick results.