My dogs wear gentle leaders. They give you control over the dog without hurting them. It takes the dog awhile to get used to it. You should make sure you follow instructions on how to fit them and how to use them for the first time.

oops . . . added comment to wrong post. Methinks Mr Bulldog is right. Someone got it backwards.

Most any tool can be abused.
I have used both e-collars and prong collars (working with trainers). The prong collar instantly changed my old girl from a dog that pulls horribly on the leash to a dog with excellent leash manners. All that was required was that pressure sensation and she slacked off on pulling. No need to tug on it. She got the message and did not challenge. I used the prong for all of one week, seven years ago, and she never got close to wounding herself. I tried the same tactic on my present pup and it didn't work...she leaned into the prong collar and it was clear she would get hurt, so I went back to a flat collar and other, slower training methods.
As for e-collars, yes, and a##hole can use them as shock collars and severely traumatize a dog. But if you work with a good trainer, you get the stim level set so low that the dog barely feels it. My lot had much worse reactions to the vibrate function of the e-collar than a calibrated low stimulus. I gave away my e-collar long ago because it seemed unnecessarily complicated for the sort of training I want. But, used correctly, with a minimal level of stimulation, they are not cruel.

The reason I hate choke chains is that so many people seem to think they are fine. They simple physics of a choke chain concentrates the force over a very small area of the dog's neck, thus the tool has potential to apply large amounts of pressure and do a lot of damage. And yes, when put on backwards they are deadly (as pointed out by Malka and MrBulldog). But they look so innocuous. Snake chains as used in the show ring are even worse from a physical point of view . . . but they are rarely used on dogs who haven't learned good leash manners.

Well said re e collars. They have been the making and saving of our dog Ben