I think they are great. I have used them while caribou hunting in Quebec to shoot grouse and ptarmigan. They worked great. Quick kills and the arrow would never go far once it hit the ground or any brush. I even used one to kill a small opossum in the back yard. I never had an arrow break. I would say get some and have fun.
I have used them for 30 years or so...They also make the arrow easier to find the little prongs help keep it from burrowing and tend to catch on grass and other things which helps stop it quicker...I've killed a ton of rabbits and squirrels with them...