The only one that I have ever used is the Primos can. Most of the time it does not work at all, even if you can see the deer they ignor it. However, sometimes they come like they are on a string. I have only had it work twice but it worked very well on those occaisions. Last year I was hunting in the river bottoms (big timber) and I could see a deer but I couldn't tell what it was. I got the can out and called a couple of times. The deer that I could see did nothing. I heard something behind me and it sounded like a deer but I couldn't see it. About that time a buck came trotting around the end of a brush top heading straight for me. The buck had to turn broadsie to go under under blow down and I mouth bleated (loud) as he came out from under the blow down. He ignored me and kept on coming. I bleated again even louder and kept on coming and looking hard for the doe. I finally shot the buck at 5 yards from the base of my tree. He was a basket rack 9 pt with palmated brow tines and a 1 inch kicker. He would have been a brusier in a couple of years but it was public ground and the guys I hunt with aren't going to pass him so.... however I digress. Sometimes the can works great for me and other times not at all but I will keep one at all times for those occaisions that it does work.