Hi, as a few of you know my dog Buster is pretty dog aggressive, so we have been working hard with him using a very good trainer and we have made a lot of progress. We have got him to sit and be quiet while another dog walks around him. However this week he seems to have gone straight back to square one. He wouldn't listen to any commands and last night at training he was a nightmare. So we decided to try a cintronella collar. She got me to walk towards other dogs and as soon as he started she used the remote to spray him. It seemed to work and he was walking a figure of eight between two dogs and not doin anything. I just wondered what other ppl thought of these and if any one has used them. They are quite expensive and so would like some reviews if possible.