Tell me about Pinch Collars vs Choke collars

Thru this whole forum, I've read that people use pinch collars to help get their dogs to walk properly and not pull when going for walks.

I've been to seeveral pet stores here in Western Australia and no pet store has seen or even heard of a pinch collar. they have choke collars here at all pet stores.

as i understand the choke collars are bad because they actually "choke" the dog. where as the pinch collars give them a pinch on the back of the neck? is this right? i saw a picture of a pinch collar and those suckers look pretty nasty. can someone tell me how they work and whether they are better than choke collars.

Nelson walks normally most of the time when we go for walks, but some times he stops to smell another dog's pee and he can be there for ages and i have to pull really hard to get him to leave. and since right now he only has a leather collar, i'm afraid i'm choking him anyway pulling so hard on his leather collar.

would a pinch collar be a good collar to get for nelson? or should i jsut walk him on his leather collar?

thanks.