I tried the Halti when my pup was younger (3-4 months) and he hated it! I also was worried about hurting his neck with it.
My dog was a puller and I used (and still occasionally do) the Sense-ation harness. I found that this was a much better method for us and I know I wasn't hurting him.
This harness has the ring in the front as opposed to the back of the harness to prevent pulling, it really does work!
Bear GSD 10/16/11
Elsa GSD 12/23/03 - 11/10/11