I used a choke for a short period when George was younger, while I was working with him on his pulling. We tried the Halti & Gentle Leader to no avail - he spent the entire time pawing his face wanting that thing OFF! I think it took about a month or so for him to realize that if he pulled I would stop walking and he would have to sit until he calmed down. NOW, as long as I put the choke chain on him (but clip the leash to his regular collar), he knows he is going for a walk and doesn't pull. SO - if him wearing his "shiny necklace" puts him on "good walking behavior", I will do it. It is only there for decoration now anyway.
I have seen too many people use chokes & prongs as "control" rather than "training". I do not feel these were their intended purposes, and personally, feel that a prong is not suitable for the Boxer breed, based on their build, personalities, etc. To train by fear and pain sends a message to the dog that may or may not bring about negative actions/reactions from the dog.